But I also accept that - until some DDOS affair is definitely traced back to his site / or / ISPs more uniformly trap port scans.. (or at least sequential ones of this magnitude) -- it's still probably the closest thing to nmap that the clueless will actually use.

And it does, at least - flag the wide-open machines. The user may not grok much, but seeing a lot of red boxes -- just may prompt a few to ask someone to tell them the obvious.

Anyone who manages to close some of those ports, finally - is one less zombie. And isn't that what we mainly bitch about? the millions who don't even know that they don't know shit?

Then again.. likely it is merely Pearls before swine.
Maybe if grc closed its doors, there'd be no perceptible change in the zombie population. But since we can't measure that, anyway - -