Sports followers generally (and usually grumpily) accept the unwritten rules of professional sports: players are entitled to make all the money they can, when and (within reason) where they can; and owners, operating within our capitalistic society, are entitled to squeeze every dollar they can from the customers (cherished as fans but treated like suckers) -- after all, nobody is forced to pay outrageous prices for tickets, parking, or beer.
So we grudgingly accept these premises, BUT:
There is an implicit understanding that team management (owners, coaches, etc.) will put their best and most competitive product on the field or court. And what KC did was to blatantly short-change its paying customers.
And that is simply not right
OK, but it's not peculiar to KC. Sports teams that can't change their position at the end of a season have long been doing this.
Fans will forgive if the players then can put on a better performance during playoffs.