I don't know why people engage with them, they want the argument, you won't win, you can't impose rationality on irrationality.
Interestingly (for me) the last rant from a motorist was when I was walking on the pavement with my kids. His issue was that I was wearing shokz headphones and my kids were on scooters - ergo (in his mind) not paying attention to his driving down the road and looking to pull in to his drive. For some reason we didn't stop, wave, say hello or something when he beeped at us.
My youngest was quite confused "why was he beeping?", "what did he want?". No point in discussing, he's just (naturally) angry.
But what it did teach me is that I don't need to be on a bike to experience the dumbass drivers, and they will do this to their neighbours so there is no avoiding them. So I might as well keep cycling.