I just read an article about a wedding cake shop refusing to bake a cake for a gay couple in the USA. If the shop owners were against inter-racial marriage and denied their service to a black/white couple this would quite rightly be illegal and unacceptable in a modern day society. How is this any difference than homophobia towards same sex couples?
Most children in my country are used to the fact that racism is illegal and immoral. If racism were legal/tolerated in a parallel universe I believe the number of racist children would be much greater. Children are born innocent but are impressionable. Making discrimination against sexuality illegal may not change the views of many adults, but it will certainly help stop young kids being infected with such bigoted hate.