You are correct in that people moving over from Reddit are accustomed to using the platform as an entertainment provider and not as an RSS aggregator. Memes are entertaining to most, so you can expect them to rise naturally. Reddit uses that specifically to attract/retain people, and most of us have gotten used to it over the years; I personally enjoy it, even.

However, this doesn’t mean you can’t use Lemmy as an RSS aggregator anymore. But we would need extra features for that, such as tags, so you can filter content out based on them. If tags existed, you could trivially filter the “meme” tag out, and it would then be up to moderators (and their bots, and the users, to report content) to make people in a community actually tag their content properly.