Sorry, to be more specific the issue I take with your criticism was more with the poll point. You didn't like that a fetish you don't like won so you made a criticism of how the poll system works, despite them working fine as is.
I'd probably say that the fly isn't grotesque in hindsight but rather falls under the idea of a "repulsive" enemy, which is probably a better way to categorize this specific fetish, a person or thing that is gross to fuck. This categorization I feel is more representative of the fetish and strikes me as probably the actual intention rather than grotesque, though I'm not a part of the game's team so I can't be 100% certain. The fly and the new enemy both easily fit within this fetish.
The first game didn't have some fetishes present in this one already. Stench/Smell fetish specifically comes to mind. Sam comes to mind to a much lesser degree, as the first game didn't have any human women. I'm sure there is probably more, but its been awhile.
Running with the premise that there needs to be basis in the first game for the fetish to be in this game seems a bit whack, IMO.
However, running with this premise it would entirely be what you would have to consider grotesque. The fat guys are probably grotesque (pretty certain it would fall under repulsive) to some, the hidden stuffed fox lady could fall under grotesque but not repulsive.