"Never attribute to malice that which is adequately explained by stupidity."

A pattern of apparent stupidity that benefits the “stupid” is not adequately explained by mere stupidity.

The fact it benefits the “stupid”, and the “stupid” keeps doing it, despite the harm it’s going to others (because malice wouldn’t even be a question if there were no harm happening) is all the evidence you need to assume malice.

Even if they are truly ignorant of the harm that’s happening, willful ignorance is malice.

Additionally lying and claiming stupidity is a common defense for the malicious who get caught. The intelligently malicious will make sure that their actions can appear to be explained by stupidity.

No, the variables of “The stupidity is a pattern” and “The stupidity benefits the one being stupid” change the equation enough that you’re the stupid one if you think that “they don’t know that they’re doing, they’re just dumb” is sufficient explanation.