In Swedish the prefix for bad stuff is the same as the prefix for not or un-. So a monster is a not-animal and a weed is ungrass. Which is especially interesting to me because that same prefix (o) is for better versions of things in Japanese.
e: This got me thinking about "plant," and I realized it's literally the verb to plant. In Swedish it's a growth, or thing that grew. Japanese and Chinese: planted thing. Spanish is also the same as the verb. I feel kinda bad we mostly talk about them in terms of farming them rather than giving them a proper name. Like if they get sentient someday, plant will probably be considered a slur.
It may actually be part of the depression. We don't know that anyone hates him, just that he believes they do.