There's a time and a place for everything.
I think halftime during a football game which is normally filled with routine fluff interviews anyway is as good a time as any. He spoke for several minutes and gave his personnel opinion. Costas has enough street cred that I think he earned 3 minutes to speak candidly about the subject during the least viewed moment of the broadcast.
Hell most of the people that got "offended" by this didn't even see it happen, they heard about it the next morning.