Developer makes X game. Regardless of how easy the game is or how little grind there is, people will still mod/cheat in the game in order to play it faster.
Developer figures, meh, people are going to cheat/mod the game anyway, let's just throw in some MTX to basically allow "official" cheating if they want to spend money.
I'm not sure how it's bad? Especially if most people playing the game without buying anything don't feel like there is excessive grind making them want to buy any of the "official" cheats. I say "most" because there will always be people that want to cheat to make a game easier and/or faster to finish no matter how easy the game is nor how short the game is.
This reminds me of the auction house uproar in Diablo III. Anyone that wanted to engage in it was already buying and selling gear in Diablo II. It wasn't hard to do, it wasn't a secret and hundreds of thousands of dollars a month exchanged hands in Diablo II as people bought and sold gear (some of the gear was so rare in D2 that you might play for 2+ years and never see the gear you want dropped in Diablo II).
Diablo III just introduced a safer way to do it (lots of people also got scammed out of their money in Diablo II on online trading sites). Oh but it's bad because Blizzard have made it official and safer and are taking a cut of it instead of the trading websites that people were using in Diablo II taking a cut of every transaction.
Bleh. All that uproar over the auction house and trading just made D3 so much worse. I could no longer trade gear with my friends when playing together. So, end result, we'd just play Diablo II instead.
It's like an extension of the rabid arguments I used to see between "people that felt people that used cheats in games were scum" and "people that didn't have time to play games using cheats so they could play and finish games in the very limited play time they had available".
I know people that would rather spend money than download a questionable cheat/mod that may or may not carry a virus payload and may or may not fuck with their game. I also know people that would rather download a questionable cheat/mod rather than pay even a single penny for "faster" progression. In the end, they both want and accomplish the same thing, but one would rather pay for it while the other would rather take the risk and not pay for it.
BTW - I'm not saying games designed around trying to force people to buy MTX are good! But from every single person I know in RL who is playing and really liking DD2, not a single one of them feels that this game was designed to force MTX sales.
Regards,
SB