And people immediately repeat the same patterns without understanding where they come from.

First, the difference is negligible between doing something ironically and just doing it. The "ironic" part stays with it, but becomes irrelevant almost immediately. The "/s" needs to exist for a similar reason. Generally it's just better to not make the /s comment at all, but if you're going to it should have the /s.

Second, if you have a couple hundred people read something and think the same response, one of them is probably going to type it.

Changing these things requires a culture shift where we encourage people to think about their comment adding something original rather than the first thing that comes to mind. You have to attack that root problem instead of the symptoms. Is it worth the effort?