Why is it offensive to claim that those who don’t follow Jesus are going to hell?

Answer by Kris Rosvold:

Nope, I don't find it offensive to assert that I'm going to a mythical place when I die, for hurting the feelers of some poor little omnipresent, pedantic, psychopathic, capricious "god".

What I  absolutely do find deeply offensive is the implied (and sometimes outright) assertion behind that statement, which says:

"You must live Our way because you aren't competent to determine your own morals."

I've got a Major Problem with that bit of flagrant bull crap and, by extension, anyone who makes such an assertion.

Why is it offensive to claim that those who don't follow Jesus are going to hell?