People do this to draw out subtle trolls into more egregious behavior that might draw actual action from mods. You're saying, then, that you genuinely intend to actually enforce rule 4? Because looking through the modlog, there is virtually zero enforcement of it, despite trolling existing in this community.
Tons of rule 3 enforcement, some rule 1, 2 and 6. Very little rule 4. Now, could we say that low effort and trolling comments are not made on here? I think that's pretty obviously not the case. So ... what's the deal with having the rule then?
You ban for mod criticism and parody accounts more than you ban for low effort or trolling. What's the deal? Is there question about what constitutes trolling? Is it the libertarian lean of a portion of the mod team? Is it just a catch-all rule to allow you to ban people you want to ban but that haven't broken another rule? The ruleset and modding of this community is on the inconsistent side in this regard, and I do think we would benefit from a little more transparency into your thinking and methodology overall.
Ultimately, trolling should be policed, due to the corrosive effect it has on the overall quality of community engagement. When one person is fucking around, other people become less likely to take the activity seriously, this is very natural. Anyone who went to school is probably familiar with the phenomenon. There was even a post in technology the other day about some researchers that got some hard data on the effects of positive and negative feelings of chat room participants towards user behavior, and it matched what I imagine is most people's anecdotal understanding. So, why is anti-trolling enforcement here so lax?
edit: Thread on the research, in case anyone missed it:
https://feddit.org/post/4067200
edit2: Has anyone on the mod team ever been a troll? Ever intentionally engaged in trolling in an online community with a goal of creating negative feelings in its users? If not, that could explain why you have difficulty recognizing the signs.