Drinking, gambling, rock music, etc. are not defined in the Bible as sins per se. Anything that comes between you and God is wrong and should be condemded but not necessarily as a sin. Anything in excess, ie that controls you, is bad.
Homosexuality is specifically denouced as a sin in the Bible. No amount of rewriting by-laws will change that. Churches that doing this are more interested in the present life of their church and placating the political winds.
If a rock music song glorifies homosexuality, is that song itself wrong to listen to?
If someone can become hooked to gambling the first time they gamble, should they have never gambled in the first place? But how will they know that they are that part of the percentage of society that gets hooked on something the first time they try it ahead of time as it would be impossible for them to know ahead of time?
Why do any denominations/churches change their stance on issues? That is what I am getting at.