I have a lot of friends and family who don't see eye to eye with me on politics, and I've told them hey, I know we have different opinions, so I'm not going to discuss it with you. And most of them are ok with that.
with your bosses, it might be a bit trickier, but I'd simply say you you'd rather not discuss politics at work, then bean dip. And keep doing it. And when they call you into their offices, do what you've been doing, and then ask if there's anything else they need, preferably work-related. HOpefully they'll get the message.