I have left other forums because I thought the behavior of the people there was despicable. I think people are rude to each other more often in forums than in real life because they are not face to face with one another. They don't have the guts to say the same things in real life. It's easier to dehumanize people because the insulter often sees the people they're attacking as just another username on the computer screen.
There are places in here that I generally stay out of because I find it too draining to bother. I think some people come here just to get a rise out of us, and get us (Christians) worked up. When we get worked up and react to the nasty things they say, they conveniently think, "Oh, look! A hypocrite! Just like I expected!" Then they use our reactions against us, as an excuse to discredit Christ and Christianity. Some people have the mindset that Christianity is wrong no matter what support is given for it.
Some of the people who "diss" Christianity may say that we have no support for what we believe. However, I think they are trying to hide that they cannot support what they believe. They will go around and around, trying to destroy the foundations of the beliefs of Christians lest they start to become convinced of anything about Jesus that you tell them. The key is not get caught up into their confusion.
By the way, it is not acceptable for non-Christians OR Christians to be rude. No one should be above the rules.
Atheists: God still loves you! Go to Him, He will give you rest. (Matthew 11:29-30)