Were people in the USSR getting barred from their constitutional duty to work?
You could be fired from your job and then put into prison for violating your constitutional duty, and no one would care.
But in practice, you were supposed to find a job that was sufficiently low-status, or was dangerous for health, or something like that. Such jobs were allowed to hire even “politically unreliable” people. (Refusing to take one of those jobs, that would be a violation of your constitutional duty.)
You could be fired from your job and then put into prison for violating your constitutional duty, and no one would care.
But in practice, you were supposed to find a job that was sufficiently low-status, or was dangerous for health, or something like that. Such jobs were allowed to hire even “politically unreliable” people. (Refusing to take one of those jobs, that would be a violation of your constitutional duty.)