"Wow this really sucks for Universal" - Nope, quite the contrary in fact. Why? Well you then immediately say a couple of the reasons...
"Now they have not one but two lands in there parks that are now DISNEY IPs. I'm aware this doesn't affect there theme park rights." - Since the theme park rights arn't affected, Universal get's to happily keep the lands/attractions of IP's Disney has to pay/maintain. As others have mentioned, this is NOT a case where Universal is promoting Disney IP's, this is a case where Disney is promoting/advertising what Universal has. In the case of Marvel, the MCU is making serious bank and keeping the IP well within relevancy for a very long time. It's the best advertising for Universal, and they don't have to spend a single penny to get it. Disney does the heavy lifting, and Universal get's the benefits.
"I doubt Disney would ever incorporate that IP into there parks." - Even better for Universal, they're taking advantage of a IP Disney's not going to use! Meanwhile, people are probably going to wonder why is Disney paying for a IP they're not going to use in the parks.
Seriously, the only way this would suck for Universal is if this changed the theme park rights and/or Disney decided to tank Marvel/Simpsons to throw them out of relevancy. But this is not changing the theme park rights, and considering how much of a cash cow the MCU is, Disney just can't tank it because that would make no sense from a company who's business is to make money. Shareholders/higher ups etc would be furiously calling for heads if that happened.
With that wonderful Marvel contract, Universal isn't just a thorn in Disney's side, it's jabbed in a major artery. If Disney ever dared to pull it out (tank the MCU/Marvel out of relevancy), it would be Disney who would suffer more from it then Universal.