The problem is with how OCD isn’t seen by the majority of the population as a serious disease. That’s what belittles it, and it creates a stigma that people suffering with the real thing have to live with every day. There are also different levels of the disease, and what someone with a mild case may find comforting humour, someone with a severe case may find very, very difficult. I get dark humour in dark situations. But with cancer, Huntingtons, AIDS, dementia etc, even with the dark humour to get you through the days everyone still knows it is serious. OCD is trivialised into “we all have a bit of that”. We don’t all jokingly say we have a bit of cancer or a bit of Huntington’s.
