You understand it correctly.

The way I see it is e.g. google images is essentially also a text search engine redirecting to the media hosts. I don't think the problem is nobody wants to host the memes but that discovery is highly censored and permissioned.

Not sure how much sense this concept makes but I think on Nostr everyone could publish a specific Event, identifiable as Meme Event, containing metadata to index (description, tags) and any amount of either URL endpoints to download or maybe a magnet URL. I think Blossom also works on media distribution (haven't looked at it yet, not sure), https://github.com/hzrd149/blossom

A meme client could then list and search these events and find every imaginable meme.

I guess the concept could be compared with what dtan.xyz does with torrents. https://dtan.xyz/