bro I've read the bible, I know tons of verses but I didn't think I had to put that in here. by the way, the bible says being gay is wrong: Leviticus 18:22 "Do not have sexual relations with a man as one does with a woman; that is detestable." in the new living translation its "Do not practice homosexuality, having sex with another man as with a woman. It is a detestable sin"
also, your Samuel 15:3 is about the removal of a country god doesn't like, and although it does talk about killing unborn children, they are just mushed in with the rest of the things Israel is commanded to kill "Go and smite Amalek, and utterly destroy all that they have"