When you log into Google, you also log into Chrome. This means that you'll have a lot of exceptions for Google websites or else a "clear history" would log you out of Chrome.
Not justifying it (I don't use chrome) but that's likely what's happening here.
I feel like the obvious thing to check here is that all chrome processes have terminated between tests. If it's still running some zombie process of course the data would persist.
At least on windows, closing chrome doesn't close the system tray process which keeps Chrome and Gemini prestaged and cached. Wonder if OP is experiencing a version of that on his Mac?
Google and the rest of the billionaire class thank you for ensuring everyone is too divided by red/blue tribalism to ever have enough unity to mount a fight against them. Well done!
Not justifying it (I don't use chrome) but that's likely what's happening here.
you are a bit out of the loop if you think this is a partisan issue, or specifically one thats only there when trump is in charge
That is a likely case. Chrome is their closed source software unlike the Chromium browser.