They deserve a place to exist but the problem with the slippery slope is when people deny it's existence they can't set up a way to prevent society from sliding down it.

It's like the euthanasia arguments. Or abortion. Corner a conservative and most will admit that in certain circumstances either can be morally justifiable, but if you allow it in that one case what's to say you don't allow it in another? Where do you draw the line?

Activism pushes things far past the point where people want it because it's the nature of the beast.

Someone who has, let's say horrible terminal cancer and is going to die miserably after a long period of pain, I think it is perfectly justifiable morally for them to suicide if they wish. But once we set up a legal precedent for it, where do we stop it? Someone just wants to kill themselves because they feel sad? That's a slippery slope "fallacy" because it skips the interim steps. But it's not an outrageous situation if you believe the initial idea that "people have a right to kill themselves".

Legally how you handle this is you let the terminal cancer patient ride it out on heroin.