I’m moderating a handful of communities, and I’ve done so on Reddit for a long while as well.

It’s generally not a good practice to stop people from discussing how things are run. If the criticism is unfounded, the mods or users can reply with why. If the criticism is valid, then it’s a good way to improve the community. What people don’t like is when mods use their power to remove criticism

Some cases where it might be ok to remove the posts might be

• the user is posting in bad faith and breaking some other rule (ex. complaints about the removal of rule breaking content, or if content in the meta post is hateful, etc.)
• the subreddit has very strict post format rules. In this case, there should be some other way to talk about the issues, such as regular meta threads or a separate meta community

In this case, I don’t think removing the post helped much. It was a low stakes discussion and the movie/TV communities on here are already very small.

It might be nice now if the mod leaves a comment about why the other post was removed, and what they’d suggest instead