This person is one-upping you only to prove to themselves that their experience was justified, by making yours unjustified. I get defensive when someone brings up a workplace I struggled with. I think the perspective of the person that put your experience down as “not-real” is attacking your experience out of defense. It’s rude and ugly, but the alternative is that “warehouses” are Not bad to work in, or that you are better at working a warehouse than they were. It might be emotionally painful to consider those alternatives, and it’s much easier to make younger workers feel overly entitled.