A)It’s sad that you couldn’t get a better job for four years. The people you describe who have labor market disadvantages, would have had a better job if they didn’t have those disadvantages. You didn’t have those disadvantages.
B)Probably you were taking the job of someone who couldn’t get anything better, and they really needed it.
C)Probably this is just another sad reflection of a maybe permanent market shift. There used to be such a thing as a “college-kid job” where peoples’ brains could be put to use and they wouldn’t be hogging the place of someone with fewer options. See also your degree is useless/you should train to be a plumber etc. Mcdonalds was for high-school kids.
D)I have done hard grinding physical labor and there is no dignity in it. I would have done something else if I could, and so would everybody else doing it. Moralizing bromides about the dignity of labor are a great hypocrisy tell.