Sinhalese Buddhists are trying to counter Muslim expansionism by violence. Whether it is ethically correct is one matter but before acting like fools they(we) should know these. Though the popular belief that expansion was by war, cutting heads cannot be correct. Romans killed scores of Christians, in a genocide, but failed to stop Christian expansion. History teach violence won't work. It may strengthen it.
Religion is about goodness not anything else. Believing a religion we try to be good. Think about this silently for some time. So logically a person changes his or her religion to be more good(may be they are deceived by someone else-but there will be a limit in mass shift of a religion). When people see something good (may be economically) the change can happen. I have read this is the case in India, cast ridden people choose to be converted as Muslims because they saw equality in it.
Buddhist thinking is beautiful but practicing it sucks. So be careful what you wish for!
We Buddhists should know facts. They can go to internet and browse independent platforms like Wikipedia and find out facts themselves. Here are few which I think useful.
The popular belief that Islam was spread through sword is incorrect. It is logical that religion is about goodness. When people see goodness in a religion they embrace it. It is the case for Buddhism, Christianity and Islam. Islam is the more modern religion so logically maybe it has rectified more errors than older religions.
I can give an example, this may or may not be happening now but happened in colonial times, but thinking about it is a good exercise for our minds. We Buddhist fawn at Catholic church, saying they convert to Christianity the Buddhists by helping the poor with money, giving education to the children or giving jobs. These are good things, not only because poor people are elevated, the feeling poor people get that they are not fully ignored by society. So it is obvious people get converted. As Buddhists if we are against it, are we Buddhist as Buddha taught us? or Buddhist of something else? We are prioritising our fundamentals before the well being of the poor.
A proposed solution
There is a sentiment in the Sinhalese majority that, Muslims make more children and Sinhalese don't, therefore is, one day Buddhist will be annihilated by Muslims.
Lets analyse this. Some say there should be a law limiting number of children to two. Why two, not one or three or complete ban. reason is majority like to have two children, ideally one boy and one girl. So, minority communities should follow. Isn't it against human rights?
Population control as a whole is a good thing, the world population is more than it can sustain. This creates most of the rifts among us. But will it justify a family with enough wealth, where the mother is extremely health and willing to have ten children, prevent doing it. Then the other extreme, a poor family who have two children, and a burden to the mother, and against her wishes father want another child. The reason may be they have two girls and father want a boy. The mother is pressed to have another child. Isn't this against women's rights?
What we can do is to change our laws and attitudes to birth control. Some religions are against birth control. All religious heads should get together and should genuinely accept birth control, and should preach and explain to their devotees it's benefits.
Then legalise abortion, it is assist women's rights to force them to have children that they don't want. Rights of living people should precede the rights of an unborn like rights of humans precedes the rights of animals.
Suppose a woman is conceived due to domestic rape, what can she do? Suffer all her life, were are her rights? We should have laws against domestic rape. And woman should have rights to do an abortion. Even in a mistake like forgetting to take the pill, she should be allowed to abort.
Well, then what are the rights of the husband? Suppose wife is continually rejecting intercourse, even the present laws allow for it. But the wife may be sick and temporally rejecting the husband, does the husband divide the wife, what will happen to the children, if divorce is, so loose?
Then comes the third precept in Buddhism. Legalise prostitution. It will help the man to temporally satisfy his urges, instead of breaking away from the wife permanently.
Legalise pornography. This will allow men to satisfy their urges without harming womenfolk.
See what a beautiful world we can have if we are prepaid to deviate from accepted norms.
There is a another angle. The behavior of the Buddhist monks are very similar to the behavior of IS(Islamic state) fighters, trying to spread Islam through the gun. Isn't this a Trojan horse, instead of converting few Buddhist to Islam, change Buddhism (the whole religion) to Islam. Though this is intentional or not, by Buddhists themselves or by Arabs, it is happening. The behavior of the monk mobs is evidence.
As Buddhists isn't it better to focus on our children(the next generation) than think about what will happen in many generations to come. By so thinking we will be destroying the future of the immediate generation(our children), by destroying the economy of the country.
Solution
1. Legalese abortion. To allow women free hand to prevent them suffering.
2. Remove third precept from Buddhism and other religions. Think this may be the most damaging part of the religion. This us a blanket ban even three year olds and sixty year olds should adhere. But the meaning of it is to safeguard children, where parents usual age is between twenty to fifty. As small children we are confused of its meaning and most of the children touching private parts (which all children do- sex is natural we all exist because of it) are scared we will go to hell. Think about the mental suffering they undergo. Then too much protection of girls makes them frigid, sexually dormant. They are sexually active only at peek, just after or before marriage, and after the first child they forget all about sex. This carries to old age. Think about male suicides at old age. When you are young and healthy you can find the comfort in alcohol or make other extra marital relations. When you are old you can't even drink and get drunk. Women will not be interested for an affair(no prostitution). Because sexually inactive women young men tend to have extra martial affairs.
3. Legalise prostitution and phonography.
4. Force all religions to accept family planning.
5. Make laws to prohibit rape inside marriage.
6. Stick enforcement of minimum age of marriage. Or better allow marriage only at first pregnancy. Marriage should be only for the sake of children, not to allow men to legally rape women. Just think how many women, Muslim or otherwise carry the burden burden of a child for ten months and suffer for another five years till the child the child goes to school, and then suffer again and again for each child for ten more times. Sri Lankan women, specially Muslim are sentenced to hell after marriage(I speak of poor people). Save the women, educate them, give them jobs, empower then economically, give them their rights, human rights. The problem may be the country is so so poor, even with attitude change it will be difficult to implement these.