When people point out logical fallacies it is almost always an expression of hypocrisy, but many logical fallacies (straw man, ad hominem, even reductio ad hitlerum), can theoretically be avoided by all parties. You don't HAVE to call your leftie buddie a communist, you CAN argue all relevant points with a MAGA hat dude without bringing up Hitler. If you're discussing concrete political or social predictions, I'm not so sure you can avoid the slippery slope argument as comfortably. At least no-one ever does.
"Slippery slope" arguments can certainly be discarded as fallacies in philosophy class or Rhetoric 101, but how would you discuss the relationship between current decisions and events and the future without them? One of the more famous arguments against Trump from the Left is that he will, or at least wants to, create a White Supremacist 50's America, much like the boomer argument against Obama was that he would make America more Islamic (or something, I don't care about these things). These are indeed stupid arguments, but only because we know that Trump isn't much of a "white racist", and that Obama was a secular capitalist shill with a bit of Scandinavian polish on him. The arguments, however, are not "illogical" or "fallacious" in any politically meaningful sense, and we can well formulate adult and even rational alternatives to them. Say "If Trump Tweets and says that NATO and the US will not defend the Baltic states unless they pay their full NATO dues, this will strengthen the geopolitical position of Russia". This is clearly "slippery slope" stuff - perhaps Putin will resign and personally head up the next Moscow Pride Parade out of sheer gratitude simply because Trump said he wouldn't back up Estonia, who knows? It's still a potentially relevant argument in a political discussion on Trump's public statements, and must be refuted with something else than wikipedia references.
To put it simpler:
"If you shoot heroin ten times a week there's a real possibility you will become a heroin addict and live in a shoe."
"SLIPPERY SLOPE ARGUMENT!"
Indeed it is - almost nothing in the realm of manifest reality and time follows logically from anything else - but the argument is still a very pertinent to the question of whether you should be shooting heroin regularly or not. Pure logic doesn't always interact well with reality, even if I agree that it is clearly the superior realm of those two.