It's an interesting article but it's not really anything new. Questionable owners have been rinsing clubs and the league for years, and not just in England. Even in Germany with their much admired 50+1 ownership model.
The crowds at Newcastle and City have been massive for years, especially at Newcastle, even in the most miserable of times under Ashley. It's a bit much to expect a club's fanbase to turn their backs, especially when they've got a chance of silverware.
Football boycotts and protests are incredibly tricky things to organise and navigate. I can't think of any that have been wholly successful. We tried one at Killie to oust our previous owner, and only a really dedicated hardcore of about 500 fans (roughly a sixth of our average gate) stayed away as part of it and were given a pretty hard time by those who didn't.