Exactly! I understand that accomodations are necessary and the pandemic really did affect people's mental health and overall ability to maintain their academics (among other things), but simply dropping the entire Winter 2020 semester disregards the fact that people actually worked hard for their grades for the 1st half of the semester. It also assumes that people react similarly to such conditions. Even though some schools offered to convert graded courses to pass/fail options, some people still chose the graded option, which I think is fair to say, requires more time/ effort (obviously this depends on the course and courseloads vary, I'm just speaking from my own experience).
Alternatively, I think the fairest way to proceed is to have different gpa calculations available, and just use the highest one. For example, giving the option to drop the Winter 2020 semester, but not making it mandatory. Obviously there would be some biases associaed with that as well, but I think that would be way better then just simply assuming that everyone's grades dipped because of this pandemic.