First responders have (in some counties had) immunity while doing their job. If grandma needs CPR you don’t want a first responder to hesitate to provide that CPR because they might crack a rib and get sued, or worse, thrown in jail.
The president should not be afraid to make decisions in fear of political retaliation, which is exactly what this ruling clarifys.
If the first responder breaks the law they are held accountable. If the president breaks the law they will be held accountable.
This doesn’t mean the president can do whatever they want and they are immune from the law. That’s ridiculous. The ruling even states that.