I think statements of the form "X is immoral" are just secular versions of "X is against God's will", in the sense that they (not necessarily intentionally) use

I think statements of the form "X is immoral" are just secular versions of "X is against God's will", in the sense that they (not necessarily intentionally) use linguistic trickery to present a personal preference as a universal rule. If I am against something I can say "I am against X"; making statements about oneself is generally safe and not an overstep. There's no obvious path from "I am against X" to "I will stop you doing X". If I say "X is wrong", that sounds like an absolute, and is more easily (ab)used as a justification for stopping others doing it. The exact same linguistic distinction applies to offence. "I am offended by X" is accurate and works fine in a society. "X is offensive" is a precursor to censorship.