In the internet we disregard copyright. Ignore it. Take the side of multi-100B dollar multi-national corporations when our sovereign or sub-sovereign governments or regional/local businesses want to enforce their copyright.
Technically, in the world of copyright, when that meme/video/clips are used, you have to license it. For example, if a news company has this story up about the NFT sale and shows a still of the viral video, they technically should contact that maker of the viral video, negotiate a license, and pay a licensing fee.
NFTs would be one way to centralize the information on who to contact for licensing and to establish who owns what.
If you think about merchandising (shirts, mugs, posters….) NFTs are a way to establish who is the copyright holder and can commission those works.
It is odd with these viral videos lately because (1) the viral videos are old and (2) the idea of the NFT showing ownership is a 21st century solution to a 20th century problem that we’ve all implicitly agreed we no longer care about. We tacitly assume that anything posted online is public domain.