Why do people tend to see BDSM or foot fetishes as particularly creepy?

I feel like people are more ready to be judgmental towards people with foot fetishes or BDSM. Why do people think it's more socially acceptable to mock people (particularly men) with foot fetishes or who are into BDSM, or consider them to be creepier than other sexual interests?

Also, before you ask, I do not have a foot fetish and don't think that BDSM accurately describes what I am into.