That's an inductive argument, not a slippery slope
argument.
All inductive arguments are fallacies, in the rigorous sense. Only
deductive
arguments are rigorously valid.
Although they are fallacies, that does not mean that inductive
arguments
should be ignored. They simply need to be recognized as
such--that
there is
necessarily an element of uncertainty about the
conclusion.
Then you're using the word "fallacy" in a different way than normal
humans use it. That might be a more correct way of using it, I don't
know, but just be aware that people will take it differently than you
mean it. Calling something a fallacy sounds like you're saying that it's
incorrect and should be completely discounted.
I don't think anybody believes that their "slippery slope" argument is
conclusive proof, we all know it's just one consideration in the
debate.
Alex