@Fragglemuppet I 100 percent agree with this; people posting YouTube links in particular are some of the worst offenders.
I will say though that third-party software (particularly targeted at screen reader users) doesn't help here, by truncating URLs and not making the visible previews available. On the Mastodon web UI, people can see a preview card next to most plain URLs so they know what they are without clicking, and people assume everybody will get that info when posting such links. @FreakyFwoof