Civil discussion is fine, but when people go beyond that they are out. The danger is that you drop down to their level which is about provoking and offending.
The vast majority of posters are not a problem.
Some just seem to have opinions which is getting into non - objective territory. Opinions are not necessarily wrong, but they can be.
Example they quote you and basically say what you said is crap and this is how it is based on their opinions without any back up evidence etc. I am sure some just do it to create a reaction and wind me in. They may not even believe what they write, but that's not their purpose in posting. Those posters are candidates for ignore.