For me it’s because the bias rating specifically is opaque and can be just plain wrong.

I could block it but if everyone who thought it was a bad idea just blocked it then it wouldn’t get downvoted which might lead people to think everyone generally agreed with it.

At least when it’s downvoted people take a step back and are less likely to just accept what it says.

EDIT: Also worth pointing out in my case at least I did go to the effort of actually trying to provide some constructive feedback on the bot through the proper channels rather than just downvoting and moving on.