One of my guilty pleasures is watching horrible things when other people aren't around.
That sounds disturbing. Why are you watching those things?
I like watching videos where people make fun of the disabled.
Watching videos of people making fun of disabled people isn't good for your mental health. Disabled people are still people and so you should not enjoy seeing them be humiliated on camera. You should work with a therapist to help reveal the reasons why you find watching such videos enjoyable and bring about positive changes to stop that maladaptive behavior.
I can do what I want and there's nothing you can do to change my mind.
If other people found out that you enjoyed seeing bad things happen to others, they're going to think that there's something wrong with you. You should talk to a mental health professional to get to the root of why do you have such a fetish and hopefully get resources to recover.