Be nice. We all make mistakes in subjects we don't know. I have a few examples in my comment history ...
Try to pick one or two comments that are wrong but not very wrong. Reply to them explaining the error(s). I like to add a Wikipedia link when available.
Ignore the very wrong comments. It's usually impossible to give a coherent reply. You only will get upset.
Also, to encourage a civil discussion try to upvote the grey comments unless they are offensive or extremely wrong.
Try to pick one or two comments that are wrong but not very wrong. Reply to them explaining the error(s). I like to add a Wikipedia link when available.
Ignore the very wrong comments. It's usually impossible to give a coherent reply. You only will get upset.
Also, to encourage a civil discussion try to upvote the grey comments unless they are offensive or extremely wrong.