I watched the programme, and from memory he did say that he wished he had seen through Epstein's lies, but stopped short of apologising for his association with him. He said that his emails (from PM to Epstein) were embarrassing and more - can't remember - but that he had no idea that the abuse was going on.
Who knows? If Epstein could get girls, he could get boys, but that has not, AFAIK, been alleged, and PM has not been charged with abuse of any kind. He said on LK that being gay meant that he was kept separate from that sort of thing. Again, I don't know - my social life doesn't include orgies, so I'm not sure how they work. I suppose it would be a bit awkward if people were pairing off and there were those there who wouldn't want to join in? A bit like having teetotallers at a wine-tasting (and I'm not being flippant - I'm just looking for a parallel). You would invite them to something different, surely? Maybe that's how Epstein worked.
If PM apologised, maybe it would implicate him further? What I do know is that he is the ultimate politician, and he will know exactly what he is, and is not, doing. I suspect there is a lot more to this than we know, but it may be some time before we find out.