I don't know what Grodd's been smoking there in Gorilla City, but he certainly doesn't look like a mind-controlling, world-dominating super-intelligent ape to me in this picture:

But whatever it is, I bet he got it off of Angar the Screamer. That's the kind of crossover I think any self-respecting love child can endorse. Peace, happiness, and evil; the sixties live again, my friends!
No, this obviously -is- the results of some new plot. Think about it for a moment…
Grodd can control people’s minds. This apparently includes hero-types.
Get Grodd, er, ‘watching the colors’, and plop him down somewhere in the middle of a city.
As local hero-types come after him[which they will; he’s a known villain, after all], Grodd just offers to ‘share the love’ or however you want to put it…presto, every hero-type in the area, as well as any normal people who didn’t get out of the way [such as, for example, law enforcement officers], are all tuned out from reality.
After this, the other plotters can do whatever they like, provided they’ve got equipment or abilities that will render them immune to Grodd’s control. [And I assume they would if they’re going to attempt this kind of stunt in the first place.]