I'd have to agree with this. I already saw the CMA lynch mob when this first started.
The CMA is legally bound to take into account any new proposals. Their job isn't to prevent mergers by any means. They're there to make sure consumers in the UK, an only the UK, are not harmed.
MS came up with a new deal and they took it into account.
The only strange thing here is that they're bending over backwards to get this done before the 18th so MS doesn't have to renegotiate with Activision, who would probably ask for more. It's a really shady move by a regulator to approve something without actually providing a proper review to the court.
The CMA probably knows they'll accept the deal so they're doing MS a solid to fast track it. The only thing that changes here is that MS will sign the deal based on agreed prices. Even if the review went past the 18th, the deal would have still gone through. The only difference would be that MS would probably have to pay more if Activision asked for it, and they probably would have.