While yes, some of this is a bit overdramatic, I agree that the event killed any and all motivation to buy the game.
Which is a "big deal", since I rarely want to buy games in the first place because I really need to be hyped for them first, and I was for this one after E3.
Now all of that excitement is gone and they definitely lost a buyer by telling Yoshi-P to make it hard to finish the event, because I don't want to see any of those little critters ever again.

Then again, it probably introduced Yokai watch to a bigger audience, so I assume they gained more buyers than they lost through this event..