its not "whataboutism" its the "oh facebook is the single biggest threat to x, y &z" its reductive and plainly bollocks.
if Facebook was editorialized, then yes, it would be the leading cause of x, y & z. Facebook is a reflection of society. How do I find out about some nefarious actor on facebook? through news, its pretty rare that I am organically exposed to that stuff.
Take Tide pods, that was a total moral panic driven by American TV. The "death bird" panic was driven by UK daytime tv. It got to the point that my Kid's school was showing the image to my kids, saying that it was ok and that its not a problem, and that you were never going to die, all the while having an expression of repressed fear.
Facebook is a Social Phased lock Loop. You have to engage with the extreme content for it to continually be shown to you.
I dislike Facebook, they have made some strategic failures. However this _obsession_ with facebook absolves everyone else, which is both the point and the risk of this stupidity.