Not familiar with the site, but reading what someone puts out on the Internet is not wrong. Like you said, you sometimes come away with useful info.
Responding with hurtful/negative comments is hateful, we must consider how we would feel reading hateful/negative comments directed at ourselves.
Talking about things among your friends maliciously is not the best, but is still considered 'kitchen table talk', as long as it does not get back to the person you're speaking about
. Another thing to consider is, how you feel after making these comments.
We all have just a little bit of that within us, some can keep it under control, others cannot, or chose not to care who they hurt.
My two cents