Contrary to your suggestion I had no pre-conceived notion, simply formed a view after reading many of the threads. Yes I've worked in companies with suggestion boxes, and have even been responsible for commissioning anonymous staff surveys. These are very beneficial, but also fundamentally different from this site.
Yes there is some material here that's interesting and could be beneficial. My point is more that it seems an unhelpful use of time to consider it likely that management will troll through these forums to discover the odd pearl of wisdom. Conduct the exercise iI mentioned, deleting these types of abuse from the threads, and yes you are probably right there is some valid feedback here.
Calling managers dogs or scum, or some other derogatory reference is of no use at all. That is, if you actually want to influence or change or heaven forbid, improve something.