lol, why everyone saying that the MC is stupid??? He is happy go lucky and clumsy, but not that stupid.
It's stated in the chapter that he's too preoccupied on logging out and checking out his fame.
They were their allies, so it will just be a bother to check every single allies level. Why bother checking out the levels when you will be logging out and won't see them again?
Also, if only you could realize,
It's only made obvious to us, the readers, and not to any character around the MC, that they were betrayers .
And to MC's viewpoint, there's no any clear indication that there are traitors in his team.