"I do and don't see anything wrong or strange with it. :/"
Smurf are not my stuff, but clearly that is worse to have your "for children" license being ... detourned in a less child friendly way than a fan doing stuff around it for free (well, this won't be the first time I see a legit fan game being thrown down while an adult one is still up and living, not that I am an expert in that... but... well...my avatar does not mean anything, at all, ok?).
that is if a choice was to be made, suing a fangame is always troublesome for everyone involved, but it is easier to say "I protected the license from a fan abusing of it to make a game that will hurt us!" I guess.
back on topic: however I am curious to see how that will end, should be interesting...