Sony's core argument against the Microsoft-Activision deal is literally "but we can't actually compete with Microsoft unless we have more exclusive deals than them."
That's it. That's the whole of Sony's argument. The only people I see defending Sony say that it's about ensuring Microsoft doesn't take anti-consumer and anti-competitive policies, but that's exactly what Sony does with their timed exclusivity crap.
I am not a fan of big corporate mergers. Historically, they end up eliminating choice and increasing cost to the consumer. The corporation benefits, and everyone else suffers. That said, Microsoft is simply playing the same game as everyone else. So part of me wants to tell the judge, in a very jingoistic way, that since Microsoft is an American company and Sony is foreign, the judge has to give added benefit to Microsoft by default. And since we're talking about an equal playing field rather than even giving Microsoft in advantage, Sony has no grounds to sue as a foreigner. Sucks to suck, but this is America, and we will prioritize America first, because that's what countries do. They put themselves before non-citizens. That's how they've always worked.
Why isn't Halo on PlayStation? What kind of an asinine question for a judge to ask. Why isn't super Mario Brothers on Xbox? Why isn't God of War on an Atari? A judge who needs to ask a question like that is so wildly incompetent as to be immediately removed from the bench by a vote of the Senate.