Yep. I think the WPScan guy doesn't understand how the GPL works... and seems to think that having a "wrapper" around it for commercial/non-commercial somehow lets him circumvent the GPL intent.
Forking the code from before the license change is an excellent way to keep free software free - and yes, I think he'll have to get permission from every prior contributor before he can legally change the license.
Forking the code from before the license change is an excellent way to keep free software free - and yes, I think he'll have to get permission from every prior contributor before he can legally change the license.