All it is, is those governments saying so...nobody has to agree and most of the world does not agree.
No, it is the government actively supporting certain sexual preferences for their own perceived self interest.
Way back when, it used to be that government favored marriage between a man a woman. They felt that it elevated the family unit and encouraged reproduction in a stable home.
However, today the government is hell bent on controlling the population, including curbing reproduction so such issues as abortion and gay marriage are now subsequently championed.