(Saint Gutfree;42020)
1) "Jesus didn't exist in the manner described in the gospels."
I don't think this is offensive, but it does make an assurtion that I would expect to be backed up. If it is said on it's own and isn't explained, I would find it mildly ignorant or rude, but I wouldn't dare call it insulting.(Saint Gutfree;42020)
2) "There is no god."
Same exact as above.(Saint Gutfree;42020)
3) "I do not believe in god."
Not at all insulting. It's a statement of belief, and I'm not sure how one could be insulted by what someone else believes. Of course, actions are a different, and could be offensive. So, in the simplest of words, it just as insulting as someone saying, "I believe in God", basically meaning it isn't insulting.(Saint Gutfree;42020)
4) "Your argument is flawed due to the use of a fallacy."
I don't find this insulting either, but I would expect an explaination just like in 1 and 2. To call someone wrong isn't wrong, but to call them wrong and not attempt to at least show them the proper direction is impolite and poor debating etiquette. (Saint Gutfree;42020)
5) "There is no evidence to support the idea that god exists."
This isn't insulting so much as it's ignorant. To insist something like this, you have to have seen all possible evidence. Because the subject is supernatural, that means there's a lot you've got to look at before you can say this. However, if someone actually did measure everything in the universe, I might be kinder to their statement, provided they still provide and explanation as in 1, 2, and 4.(Saint Gutfree;42020)
6) "There is no evidence to support the idea that god exists and there is considerable evidence suggesting god does not exist."
The first part is ignorant for the same reason as 5, and just plain dumb in the second part. There is no way you can prove something doesn't exist. You can't prove a negative, especially supernatural negatives. It's very much like Schrodinger's cat, I like to think.Does this answer your question?