[PaulHoule]

Accusations against MDPI, Frontiers and such take this form

https://en.wikipedia.org/wiki/Predatory_publishing

the claim is that they are ripping off the scientists. Note

https://en.wikipedia.org/wiki/Jeffrey_Beall

was forced to retract his claim that MDPI was predatory.

[kragen]

some do take that form, yes; others are simply complaints that tenure and hiring boards were going to have to evaluate the quality of candidates' research for themselves because mdpi wasn't doing it for them