Don't want to put words in your mouth but are you saying Grumpy is just trolling here?
To my recollection, he has said (consistently, and since day one) that Grantham was a scheme over technique DC, and that you'd see the defense reacting slower and being less good at fundamentals as the years went on. So far, he seems to be on track, as the defense was demonstrably better last year (again, so far) with comparable talent.
He also said that JHC, while perhaps a half-step slow to be a safety at the highest level, was a legit 5* player and would be great in run support (and good in pass coverage). He seems to be pretty on target there too.
His last prediction was that Wiggins was a 2* player with a 5* mouth. That might not be a very nice thing to say, and the jury is still out on how good a coverage corner Wiggins will be.
As for the Stoops comparison, I think there's a difference between a rival fan saying "your coach will suck because you suck blah blah blah" and what Grumpy offered, which was a very specific critique of Grantham based in experience following (closely) the team he coached previously. You guys obviously didn't like what he had to say, and I get that, but to say he's just a troll who shows up when it suits him is a little pejorative. JMO.