Except very few people are saying "Let's kill all of Group B", especially in 2019, at Google, in San Francisco. But sure, if you want to act on your "intolerance" for that specific flavor of intolerance, then please go to eg Indiana and protest the actual KKK.

Rather what "Person A" is likely to have said is something civil that clashes with the dominant political team's reality distortion field. Rather than having to address the substance, those who disagree feign highly personal reactions as if a minority viewpoint is that "kill all" mortal threat, effectively resorting to the age old monkey status games for silencing dissent.