The thing is the definition of biotoy is very loose, because some people have depicted fluffies as very unnatural in their manners, while others have depicted fluffies have very natural and animalistic in nature. I know enough people who consider fluffies to be “animals marketed as toys” jus as there are people who depict fluffies as “not animal at all”. It becomes a matter of headcanon, because different people have different ideas on them. I did an entire writeup about this difficulty of classifying fluffies and the problems with the biotoy definition.
The thing is, this stupidity is varied per depiction. Some people depict them as merely naive and.or oblivious, coming from a comfortable background, while others have them to be rock stupid, incapable of anything. However, for a supposed invasive species, this idea that they’re rock stupid wouldn’t work as well, especially in more gritty/realistic stories, because it begs too much belief that a species thats rock stupid can thrive so much based purely on “fast reproduction”. Invasive species get the way they are due to a lack of competition, and also have advantages that beat out their competitors.
Suffice to say is that I’m a bit critical of overly-portraying fluffies as stupid or dumb. Granted, I will admit that their mental capabilities may be stunted, but that doesn’t mean I’d see the overall race as inherently “rock-stupid”.