I think it's more like "fuck sitting on the train for 40 minutes next to someone who is laying across a row of seats literally covered in their own waste." If you ever get onto a crowded BART and see a conspicuously unoccupied area, don't be tempted to venture near it.

It's certainly not a judgment of that person. It's just not how you want to spend your commute. Clearly that person is not healthy, and the entire situation is not healthy for anyone.