Taking an expansive view of Hellenistic culture during the first and second centuries CE, one would expect that Paul and other writers would have very explicitly addressed sexual restrictions, if they had intended to significantly alter common mores.

The fact that they write about sexuality only in passing, especially when we look at the words they actually used in Greek, seems to suggest that they didn’t really care about sex the way later Christians came to.

Sexual attitudes at the time, after all, were very permissive. If Paul had wanted to change that, one would suppose that he would actually have said so in so many words.