If you're wanting to avoid swearing (specifically the "hard" swears like fuck and a few others that I won't mention), then go for lighter ones that are pretty much everyday language for some people. If you want to avoid any use at all, maybe take a look at how CS Lewis did his dialogues since he was an extremely devout christian. If you want to write a story that has a bit of everything, find a person or personality to emulate and inspire the writing itself.
It doesn't matter if you're Jesus and have never uttered a single foul word or if you're worse than a sailor with tourrette's. Writing an engaging dialogue isn't automatically tied to your beliefs and the best example of that is Hugh Hefner. His Jewish upbringing basically prohibited him from creating the media empire he did, but his original focus was on telling the stories (which are still good to this day), the part that everyone thinks of was more of the gimmick to get sales. The gimmick here on this site happens to be swearing and smut, so go crazy and just write in a style you feel best suits your needs based on the story you want to tell.
Edit: To answer the title, just tell them whoever they like sucks. It works with everyone, trust me. I told someone Linkin Park sucks and they were triggered, best part is I had no idea who they were.
It doesn't matter if you're Jesus and have never uttered a single foul word or if you're worse than a sailor with tourrette's. Writing an engaging dialogue isn't automatically tied to your beliefs and the best example of that is Hugh Hefner. His Jewish upbringing basically prohibited him from creating the media empire he did, but his original focus was on telling the stories (which are still good to this day), the part that everyone thinks of was more of the gimmick to get sales. The gimmick here on this site happens to be swearing and smut, so go crazy and just write in a style you feel best suits your needs based on the story you want to tell.
Edit: To answer the title, just tell them whoever they like sucks. It works with everyone, trust me. I told someone Linkin Park sucks and they were triggered, best part is I had no idea who they were.