> There's an whole genre of musicians focusing only on creating royalty free covers
There is no such thing as a “royalty free cover”. Either it is a full on faithful cover, which you can perform as long as license fees are paid, and in which case both the performer and the original songwriter get royalties, or it is a “transformative cover” which requires negotiation with the publisher/rights owner (and in that case IP ownership will probably be split between songwriter and performer depending on their agreement).
(Not an IP lawyer myself so someone can correct me.)
Furthermore, in countries where I know how it works as a venue owner you pay the rights organization a fixed sum per month or year and you are good to go and play any track you want. It thus makes no difference to you whether you play the original or a cover.
Have you considered that it is simply singers-performers who like to sing and would like to earn a bit of money from it, but don’t have many original songs if their own?
> It's parasitism of art
If we assume covers are parasitism of art, by that logic would your comment, which is very similar to dozens I have seen on this topic in recent months, be parasitism of discourse?
Jokes aside, a significant number of covers I have heard at cafes over years are actually quite decent, and I would certainly not call that parasitic in any way.
Even pretending they were, if you compare between artists specialising in covers and big tech trying to expropriate IP, insert itself as a middleman and arbiter for information access, devalue art for profit, etc., I am not sure they are even close in terms of the scale of parasitism.