I may be almost 20 yo but man I don't understand the references you guys are saying......
In Japan they categorize people as Herbivores or Carnivores. Herbivores are passive romantics, they wait to be picked up or are too shy, self-conscious or what have you rather than actively seeking out relationships. Carnivores are the people who actively, and sometimes aggressively, seek out their relationships. Recently more men have been described as Herbivores and women as Carnivores. This is also why you might hear characters refer to sexual conquests as "devouring" or "consuming" or some other adjective of eating.
In one of the earlier chapters, one of the pages didn't load properly and it made it look like the author baited NTR into the series, which they didn't. The chapter that didn't load properly demonstrates that it really isn't NTR of any sort. Then the shirt she's wearing is something people are connecting to that since the guy in the previous chapter appeared to be more carnivorous than the MC guy who would be classed as Herbivorous.
tl;dr they're confused.
Hope I explained that well enough.