Not GP, but looking at the relative difference graph[1] two hypotheses occur to me:
1) Most of the categories that are over-represented are ones that individuals watch out of obligation, rather than desire. A large portion of people watch documentaries (and biographies/historical films) because they feel they "should", because they feel like they should learn something.
Same for drama - these often include Oscar-bait that many people watch exclusively because it's nominated, not because they're actually interested in the movie itself.
Likewise, animation is (by volume) mostly synonymous with children's entertainment, so there are going to be a lot parents forced to watch what their kids are watching.
All of these line up with OP's hypothesis of obligation over choice.
2) War and westerns being overrepresented, well... film critics historically have a reputation of being Men of a Certain Social Demographic, and this is likely reflected even in modern film critic culture.
1) Most of the categories that are over-represented are ones that individuals watch out of obligation, rather than desire. A large portion of people watch documentaries (and biographies/historical films) because they feel they "should", because they feel like they should learn something.
Same for drama - these often include Oscar-bait that many people watch exclusively because it's nominated, not because they're actually interested in the movie itself.
Likewise, animation is (by volume) mostly synonymous with children's entertainment, so there are going to be a lot parents forced to watch what their kids are watching.
All of these line up with OP's hypothesis of obligation over choice.
2) War and westerns being overrepresented, well... film critics historically have a reputation of being Men of a Certain Social Demographic, and this is likely reflected even in modern film critic culture.
[1] https://stephenfollows.com/wp-content/uploads/2021/03/Differ...