You must be joking? You encouraged political activism at work and are surprised it led to problems? Is political activism code for “so long as it follows my politics”? Would you encourage a pro-lifer to be just as active as pro-choices? In any company I’ve worked at, the answer would be no.
People always seem to be surprised that others think differently than they do. I really can’t believe the hubris that goes into that. When talking to people (who suck at discourse) who think they are tolerant, but really aren’t, the conversation almost always devolves to “you’re a Nazi”. When talking to people (who suck at discourse) who think are very right wing, the conversation tends to devolve into something about how God made people/ the world / etc.
The easiest thing is just give people three PTO days that don’t carry that you encourage to use for civic purposes, but don’t enforce, and maybe set up a matching donation up to $X for any org with the valid paperwork.