That’s something I don’t understand. Things I believe in are buttressed by some sort of reality. I can’t turn belief on or off just by willing it so. Can you?
A forced conversion isn’t a conversion at all, I think. Can you decide to believe in something just because you are told to, with no evidence of it being true?
A casual Christian isn't really a Christian, so if they lose their "faith" they haven't lost anything.
Now as to conversion to Islam, imagine Europeans are required to join the NAZI or communist party and contribute financially to it and work for it.
They fall in line because they are required to. And they pretend to be true believers lest they be accused of apostasy and executed.
I think a lot of muslims are just controlled by Islam and are not true believers.
I think that's why the Left likes Islam. It is a proven means of population control/domination.
I lost the ability to 'believe' when I was nine years old. Until that age, I was capable of accepting a truth, merely because an authority figure asserted it.
I will admit that there are some things in life that I've willingly chosen to believe are true - even without solid evidence - but I tend to base that belief on rational conclusions and subjective reasoning.
You've posed a tantalizingly philosophical question that could easily generate an epic thread.