For me it was that and their unqualified support of H-1B visas.

The ACM always said it wanted to build bridges with practitioners but paywalled journals aren't the way to do it.

I would be 100% for more green cards or a better guestworker program of some kind, but I've seen so many good people on H-1Bs twisted into knots... Like the time the startup I was working for hired a new HR head and two weeks in treated an H-1B so bad the HR person quit. I wanted to tell this guy "your skills are in demand and you could get a job across the street" but that's wasn't true.

I joined the IEEE Computer Society because it had a policy to not have a policy which I could accept.