The other irony here is, the entire gaming industry follows what that group of people does with their money. If they buy lots of FPSs, the gaming industry makes more FPSs. If they buy lots of RPGs, the gaming industry makes more RPGs. If they buy lots of games with microtransactions, the gaming industry puts microtransactions in more and more games. Gamers are the ones in control in this interaction. Which means that, if they don't want the merger to be successful, all they have to do is not buy games from those companies anymore.

Now, why would a group of people with all of the control decide that they need to exert their control through the courts instead of through the markets? I'll tell you why: it's because they can't help themselves. This is a group of people with the collective impulse control of a two-year-old. They can't stop themselves from giving money to Microsoft no matter how shitty the games might be post-merger, and they see the lawsuit as an easier option than actually learning impulse control skills like any other reasonable adult. This is not a sympathetic position; this is hundreds of thousands of people simply refusing to grow up.

TL;DR: This lawsuit represents gamers begging the world around them to do the job of being mature on their behalf, instead of sucking it up and growing the self-discipline necessary to make their own choices about how they spend their money.