sure, but the rudeness could be much stronger, too, so this doesn't appear malicious.

It could have been stronger but it wasn't necessary either. Civil discussion is better.

I'm offended by your complaints. See how quickly this gets out of hand.

Calling bullshit bullshit is not rude. Not all opinions are equal.

You can call bullshit without being rude, true, but you can also be rude. For example, "This is not at all true." is less rude than "This is pretty fine high level grade bullshit."