It's explained in the post. The FTC accused them of being anti-competitive. The only way to show you're not anti-competitive is to demand documents of your opponents that demonstrate you still have competition.
Breaking them up or taking actual action against them would require deeper investigation with FTC taking the lead rather than potentially handing sensitive documents over to the offending company.
If the company wants to fight the block of acquisitions would foot the bill for everyone being supeonaed along with the FTC's expenses regardless of the case's success.
Wait? What?
It seems like a pretty strange position to just assume that the government is always right. I mean, if I said, all people the police arrest are probably guilty and should go to jail, I would hope you'd disagree.
Big cases against big companies are different. Since the company will have (nearly) unlimited resources to fight, the FTC will only bring a case if they're pretty sure they can win, otherwise it will be a big waste of money all around.
It's really not anything like the police arresting people.