Whether it should be seen as exceptionally offensive or not is another matter, but it just isn't by most people.

If I'm playing boardgames with non-member friends and someone does something to hinder a different player or barely beats their score, it's not uncommon to see a big grin from one and the other responds with "Oh f*** you"

I've had friends want to hang out with me and told them I have a church thing to do (while stipulating that it's not a fun church thing and I'd rather do the fun thing) and one night say "C'mon man, f*** the Mormons and come to the game with us" or something.

I'm not a fan of the language but it's also useful to realize that for many people it's not inherently offensive, it's just a standard part of their lexicon