It's only a fallacy if it isn't relevant, and it's very much relevant.
Relevancy to the topic isn't a necessary quality for an argument to be a fallacy or not? And it is a slippery slope fallacy cause the argument is that if we remove ASI being locked down to races, we will also lose racial abilities. The the "slippery slope" is that we are setting on a path where all uniqueness in races is going to be removed. Though I don't think anyone has argued for removing racial abilities at all? In fact, I'd argue they do a lot more for racial uniqueness than ASIs and are usually something any class can benefit from.
A fallacy is a fallacy because it is flawed reasoning behind an argument, or because an argument is being used in a manner that is irrelevant to what you are discussing. You cannot commit a godwin fallacy when you are literally discussing Nazis, for example. A slippery slope argument is not by itself a fallacy. They're arguing that removing racial attributes is good because it evens playing field between races so that everyone can excel equally at every class. @Scribe argues that racial traits means they won't be equally excelling at every class anyway, and wonders why racial traits shouldn't be removed as well by their line of argument. This is not a fallacy.
Well, granted, the "When does it simply become 'forget about different races'" would be a fallacy if made as an assertion that this is what they want. But that isn't the argument.
I apologize if I misread it, it seemed like that was the direction their logic was going because they moved it toward the extreme of race no longer being meaningful which is what I thought was a slippery slope but I might just be reading into the "When does it simply become 'forget about different races'." line too much.
