Like the U.S. is preventing others from doing their part. Ok. This sounds like real weak excuse. That's why the current administration is asking them to step up. It's Trump's fault that most of the NATO nations who agreed to reach 2% in 2014 (surprise, guess who wasn't president) and halfway there most haven't and have little intention to do so. If the U.S. is happy to have dependent allies then the allies of the U.S. are happy to be their dependents. That's how a symbiotic relationship works. There is an easy solution to getting out from under the boot of the U.S. Start a new defensive organization, exclude the U.S. and pay for things themselves. Do you think they will do that? An easier way might be to contribute their 2%. Otherwise, I say quit complaining about being dependent upon the U.S.
Please, point out what this supposed fluff in the US spending is that it could cut without losing military ability if the Europeans did it instead. NO ONE so far has been able to substantiate what this might even be.
The Europeans, like the US, used the "peace dividend" to reduce military spending at the demise of the Soviet Union. No one in NATO has been spending on stuff that might be needful in the case of a Russian re-militarization. The US just as little as anyone else. There is currently no US military spending that I can discern that would be redundant capacity to confront Russia with.
Just point to what it is the US would like not NOT spend on that it spends ON BEHALF of its NATO allies, and would otherwise be happy to be rid of.
The European NATO dilemma is that their military spending is still mostly tailored to the situation where Russia is all peaceful and unthreatening, and the actual military spending is geared towards providing back-up to the US in military intervention anywhere in the world EXCEPT Europe itself.
Mostly Trump is just insultingly wrong about what the fundamental problem is. But then he LIKES Russia for reasons not entirely transparent, while he actively dislikes his European allies. (And no one really bothers to assume things need to make sense where Trump is involved anymore. Since it won't.)