I think that its easy to explain what is happening because the Mods are unpaid and only do it as volunteers.
That means that they have to feel that they are getting something out of it and the only thing available is that it can give them a feeling of exerting power.
We all know that a power complex can result in an escalating range of extreme actions, Sadam is perhaps a good example.
A good mod would rarely need do anything at all and would send a private email if he was starting to be concerned about anything.
All this unnecessary deleting and locking of postings which are not rude or abusive imply they are just boosting their power complex.
Tony