Probably because corporate executives are asshole control freaks, so even if it's only 23% (according to the other responder using Forbes' own quote), they get

Probably because corporate executives are asshole control freaks, so even if it's only 23% (according to the other responder using Forbes' own quote), they get pissed off and want to "fix" that. Also, nearly a quarter of viewers using ad-blockers still amounts to a lot of "lost" ad revenue, even if it's still a minority. (Using scare-quotes since you're not losing something if you never had it, but corporate executives don't believe that; just ask the MPAA and RIAA.)