I used to travel, a lot. And I spent a lot of time living out of hotel rooms, some fairly upscale, some not so much.
This is something I've long suspected. It doesn't make me any happier to have my suspicions confirmed.
And this why I always carried a small can of Lysol and a pack of sanitizing wipes.
And I never used the room cups, I brought my own travel mug and used that. However, it occurs to me now, that the room coffee maker was probably getting the same treatment.