I've known people who managed union employees. While being walked out (fired) for bad performance, they learned the magic words "I have a drug problem". Automatically reverses firing, employee goes to some (company paid rehab) for 1-3 months, gets their job back. They just use this as an option to keep their job, they dont even care. Every "compassionate" benefit you offer will be equally exploited by losers. It seems to me a zero-sum game.
The exceptional number of people I've known in Unions for decades are mostly career professionals with good professional ethics. Your anecdata vs mine. I hear garbage like that from anti-union people but have never seen that in reality. Is it a union for bank robbers?