This is getting worse and worse. I have been asked my full SSN, passport number, graduate and postgraduate diplomas and the funniest of them all - COVID vaccination card, for a remote job. lol.
8 times out of 10, saying no to these ridiculous demands gets accepted. But I have had cases where the recruiter would simply say they cannot proceed without getting everything they asked for.
I think it depends on your situation. Do you really need that job? If you're confident of finding another job, then it would make sense to tell them to get lost. I used to give them everything they asked for, I don't do that anymore. These shitty behavior can only be stopped if more people say no. What are they gonna do with a 20-25 year old high school diploma? Makes no sense, it is just some kind of power trip...