Down-voting every youtube link is indeed the only individual action that can be taken in the current system. It could theoretically lead to a YT link being folded or sunk lower. Tricky though because people should know why their YT links get down-voted. Ideally you would be able to tell them in a response. But I think I know how that would go: people with digital inclusion principles have actually become a diluted small minority in the fedi. A flood of lemmy.world folks who would follow the crowd off a cliff would down-vote your reply and up-vote the YT link in solidarity of their favorite walled gardens.
You could DM the reason for down-voting. But then the problem does not get the exposure it needs.
The fedi has evolved like Burning Man. The movement was true to its founding principles early on but as the crowd grew over the years it became enshittified faster than a digital rights subculture could take hold.
BTW, I should mention that sh.itjust.works is also a centralised Cloudflare node.
It’s a decent approach but incomplete. Couple problems:
A good system is designed with the assumption that users are lazy. As such, Lemmy is poorly designed.
1 lazy author can inconvenience thousands of readers. Lammy’s design fails to address that.