Not necessarily in opposition. But I find it funny that the words you chose are all still words used in a medical sense before the new millennium, with similar ableist connotations - just ones further removed by time.

Dumb meaning mute, as in "deaf, dumb and blind", and with moron and idiot meaning "mild" to "profound" intellectual disability respectively. Similar words like "imbecile" or "cretin" held similar connotations. All of which the r-word was once adopted to get around, until it was picked up by the public in the same way,

The Wikipedia rabbit hole led me to the "euphemism treadmill", which in turn led me to the "List of disability-related terms with negative connotations", many of which replaced each other in "formal" usage at different points in time.

Again, not against trying to avoid hurting people. It's just that trying to get ahead of this sort of thing is amusingly circular when viewed in the abstract.

What exactly are you trying to say when you say "dumbass" or "moron" or "idiot"? You obviously can't mean "mentally deficient" in any measurable sense, certainly not a "low IQ". You must therefore mean something like "foolish" or "stupid", acting unwisely or impulsively, or without reason. But is that how you're using them? Is that how they're used generally?