You're absolutely right.Its a terrible argument. Like fans are just obliged to buy all the mediocre Star Fox Adventures and Star Fox Command games just because they have Star Fox in the title. Like its the fans fault you decided to make a game that wasn't like everyone's favorite entry in the series, Star Fox 64/Star Fox 2
"Gee whiz, people didn't buy DmC, I guess we can just cancel DMC5 and future installments, fans just don't want more Devil May Cry games! No other logical conclusion can be drawn from this turn of events!"
Still, I think it's understandable to be excited that Nintendo is working on Star Fox.
It has more of a chance of being good than if it weren't being made at all.