Who is "they"?
Social Security Disability Insurance pays benefits to you and certain members of your family if you are "insured," meaning that you worked long enough and paid Social Security taxes.
“They” is everyone who receives SS benefits. There’s a reason the word “insured” is in quotation marks in your post: it isn’t insurance. There is no system into which you pay SS taxes. They aren’t SS taxes, really. Call them payroll or just another income tax, if you want a better description. Supposed SS taxes get shovelled onto a big pile out of which all government expenditures are made. By the time you retire your money is gone. Should you receive benefits, that money will have been taken from someone else.
They only ever called it “insurance” to make it respectable. That charade didn’t last, as we all refer to it rightly now as an entitlement and wealth redistribution program. I notice people referring to unemployment “insurance” less as insurance and mote as the neutral benefits. That’s a step in a saner direction, too.
You may say the money they confiscated—or, in fantasy socialismland, to which you “contributed”—morally ought to come back, even if there’s no accounting connection. But two wrongs don’t make a right. Those who believe in it, methinks, recognize the argument is paper thin, too. Why do you get back payroll taxes and not, say, basically every other tax?