Some scientific research shows that having a different sexual orientation naturally happens in many spices including apes, cats, dogs, etc. As you mentioned it is somehow similar to being left-handed in a community with right-handed majority.
Surely there are some physical and psychological differences between left-handed and right-handed people, but it doesn't mean that one should blame left-handed people or force them to write by their right hand just because write-handed people are majority of the community!
The same is true for LGBT people. We can't and shouldn't deny or annoy them just because they are different from us. Conversely a civilized and developed society should provide some appropriate options and opportunities for its minorities including LGBT people.
About the situation of LGBT community in different countries, as far as I know due to historical and cultural reasons there are many people with alternative sexual orientations in Israel and all Arabian countries of Middle East. However there is a big difference in their rights and degree of freedom.
Due to religious reasons in Muslim Arabian countries LGBT people are very limited and have almost no social rights but Israel is one of the most LGBT friendly countries of the world as well as being a religious state in many aspects. See the following Wikipedia article which confirms there are too many LGBT people and too few anti-LGBT rules here and LGBT community is very active and popular in Israel society. In some sense Israel is the paradise of LGBT people! Tel-Aviv itself has the credit of being LGBT capital of Middle East!
LGBT people have their own rights and pride parades in almost all large cities of the country including Tel-Aviv and even Jerusalem where they recently had a LGBT parade! Note that Jerusalem is the city of Western Wall and one of the holiest cities of the world for almost all major religions!
About mathematics education and LGBT people, I think there is no relevance and if there is any it is not negative. For example Alan Turing was a gay and a prominent mathematician. Also I personally know many LGBT mathematics teachers and students in universities of Israel who are my colleagues and have no problem in their career.