Seems fair. They charge for online collaboration through NSO. This is another online feature.
There's this recurring theme I'm seeing where when Nintendo does something price-wise people act like it's the end of the world. And, almost every time, the other big dogs have already done it, and typically worse.
The reality is 80 dollars is about expected for a flagship game. 450 dollars is the cheapest console around. And, NSO is the cheapest subscription. I think people percieve Nintendo as making kiddy games so they expect kiddy prices. The problem is, that doesn't mean the games are cheap to produce.