I will only say that it is sad that a good wholesome debate nearly always ends this way on CBF.
There is nothing wrong with a good old wrangle where opinions differ, it can be quite enlightening. Just because someone questions your view doesn't mean it's time to leave or for the topic to end.
I love a good discussion and as long as it isn't allowed to descend into insults it can be very interesting.
As for telling someone you think they are thick, it isn't that bad, but maybe a little hurtful

Let's have some hearty debates like adults do, and not get upset.