In a comversation among religious people I find nothing wrong with equating one sin to another. In fact, sages say, that even though some sins are more serious than others regarding the act itself, all intentional sins are equal by the fact that it is to rebel against Hashem.
But in a pluralist environment it's not convenient to say that homosexuality is like murder.
Murder is clearly evil to every rational. Homosexuality does not harm others ( and even if you believe it brings damage to the earth, secular won't agree)
Gay adoption is also crearly evil, it deprives children of having a father and mother, it forces them to approve homosexuality whether they want or not ( a child will very unlikely be able to express his own opinion, if his parents are a gay couple), it is indoctrination, selfishness, perverts the purpose of parenthood and is Nazi. All this can be understood by reason. If we want to win the debates and stop this Nazi laws, we must focus on this.
Equating gays to murderers in that context will not help. (not only because of non-belivers, but also because of many believers like some Christians who have a less stringent aproach to gays)