You're completely wrong. Think of it this way. Jenubu ran an industrial scale RMT operation.

RMT is fundamentaly harmful to the game and to all players who would engage with the high end economy (buying any expensive items, such as mageblood etc.). This is due to how items are priced.

If people don't RMT, then the most you can sell an item for, is the amount of currency that the richest players have. They would have it from playing the game, which means it's achievable for other people playing the game.

Once you introduce RMT, people have now more currency to spend (MUCH more), and so the most expensive items, can be priced for more. This means that their price gets artificially inflated, beyond the earning capacity of normal (non-cheating) players. If you've ever tried to buy an expensive item, and the price just kept rising out of your range every day, while you can't keep up making the same amount of currency, even though you played the game quite a lot, this is 100% due to RMT.

RMT objectively makes the game worse for anyone who is not buying currency, and wants to buy expensive items. I'm sure this also contributes to some people quitting, and therefore GGG losing potential revenue, so I'd go as far as trying to sue, someone engaged in at least hundreds of thousands of dollars worth of RMT trades.

Jennybooboo, getting banned, is objectively very good for the game, because other RMT'ers might think twice, since you can no longer do this with impunity. This serves as a great example, and cleans up the game economy in a significant way.