It was never a fallacy in the 1st place- people keep using it wrong. It's only a slippery slope fallacy when using deductive reasoning to make a definitive statement that a will lead to z. Saying a will lead to b will lead to... -> y leads to z using inductive reasoning is not a fallacy at all.

It's the difference between saying "Letting gays have sex will lead to children being married to dogs" and "If we allow gays to marry, we compromise the sanctity of marriage and weaken the moral fiber of our society. Continued loosening of our moral standards could lead to other taboos such as bestiality and paedophilia being normalised too".

In the 1st instance, it is a fallacy because there's no logical connection between the 2 points. In the second instance, there is a logical chain of possible events that could lead up to the feared outcome. It is not stated that this is a certainty or the only outcome and thus it is not fallacious.