While the author didn't mention the GPL specifically, he did mention that licensing was a consideration: Then I was in a very long and intense meeting with a p

While the author didn't mention the GPL specifically, he did mention that licensing was a consideration: Then I was in a very long and intense meeting with a potentially major customer for an on-premises install, and one of their basic requirements was “no AGPL in the stack”. Perhaps GPL was close enough to AGPL that it made MySQL's license problematic.