I think suicide is normally considered a sin in the Muslim religion too. After all, like Christianity, the Muslim religion is based on rules of conduct written in the Old Testament (+ the life and teachings of Mohammed). The same basic moral codes were originally laid down for Judaism, Christianity, and Islam...in the Old Testament...by the same group of prophets. They all consider suicide a sin.

The fact that some Muslims have rationalized themselves around that somehow means just this: they're just as prone to rationalism and hypocrisy as the rest of us are! ;-)

They're just as able to reinterpret their own holy books as the rest of us are.

Nothing unusual about that.