But then again we are paying to buy chests which are merely pixels

Not exactly following what your point is here.
The comment was supposed to quote under wolves, meaning, someone buying wings for $500 is basically doing the same as someone buying chests except one is against the tos.
Quote me if I'm wrong
Right, someone buys virtual items using real money in both instances, the difference is who receives the money.
If someone were to sell their virtual items to other players, they are essentially scamming otm because the virtual items belong to otm, not the players. In this case, the seller gets the money, not otm, and that is against the tos.
It's not that selling virtual items to other players is wrong because it's against tos, it's because you would be scamming otm in the process.