Whether the substance of this is true or not, it seems unwise to have posted it. It probably felt good to write, but now there's a real risk that future employers will perceive it as a negative signal. ("If we hire this guy, will he air all our dirty laundry in public if it doesn't work out?")

I have thoughts about whether his perceptions are accurate, but I mostly just want to say: kids, if you're thinking of writing something like this, probably don't. Go out for drinks with a friend and vent one on one instead.