Also, its important to think of the other side of the made in the U.S.A. label which was to bring foreign manufacturers to the states for our market. Think Honda and Toyota. Getting the majority of the parts made here and the assembly here was a major benefit to those areas it affected compared to having that all happen in Japan. If you required 100% or close to it, would that have even happened?
There are both positives and negatives to the current system, but in a global market I'm not sure it's sane to expect complex products with many parts to have a single national origin.
Some engine components, some drivetrain components, all the electricals, all the suspension, and wheels are all made outside the US. That leaves the frame/body panels and some engine/drivetrain components as the only stuff sourced in the US - and yes, the engine/bike assembled in the US.
And so do Toyota and Honda for the vehicles that are made here, but even those are only a certain percentage, which allows them to say so. It's the same playing field, so I don't really think it matters. And honestly, I think most people if pressed care that it's assembled here by people here and that at least most the parts are from here, especially major parts.
Beyond that it's just corporate branding and PR, and as long as they're all playing by the same rules and people generally understand and agree with it (which I think they do, and if they don't I think if they were pressed to think about it they would come to understand fairly quickly and think it's mostly okay if presented all the facts), so I have a hard time getting thinking it's all that big of a deal, as long as the majority of U.S. sold bikes are made in the U.S. and bikes sold elsewhere are made wherever. I do think it's all a bit stupid and a big PITA, but they all do it so they're all stupid and weird in the same way.
Note: I'm not really sure why people decided to downvote you instead of engage, it's not like I think your POV on HD is invalid, just different than how I see it, so I gave you an upvote to counteract it a little. Maybe someone else can do the same. Seemed a shame to have a valid position not given any discussion.
Then again this would give foreign made products a running start (Amazon Chineseum that's 3x the cost of Aliexpress - 70% made in the US!), and it would probably be only that last 20-30% that actually resulted in domestic blue collar jobs which are the ostensible desire of such labeling.
And you would be able to produce paperwork and find experts who would value it at either, or anywhere in the middle. (since there is no market price for highly specialist circuit boards which can't be sold to anyone else).
[UK tax authority]
And thats where the fact engine ECU's are useless to anyone else comes into it - their market value can be near nil.
Seriously, tech guys think they've found magical hacks in the law and don't realize that there are literally thousands of lawyers, accountants, and investors that found the loophole first, exploited it, and then moved on to the next loophole when the legislators closed the one they were using.
The "exploit" you described was possible in the 00s. And it was closed over a decade ago.
On the other hand, if I bought a wooden spoon, or even a saucepan, and it said "Made in USA" on it, and I found out that it wasn't 100% made in the USA from materials produced here, I'd feel differently because those are relatively simple products (compared to a motorcycle) where every piece much more crucially defines the whole.
I don't know what the cutoff is, though: a product doesn't have to be 100% USA-made components, but 51% would be too little. Ballpark, 70%+ would be the over-under where I'd start to feel misled.
How about designers not in USA?
(My 2016 Mac Pro also said Made in the USA, as it was in Texas.)
It's very difficult being a Mechanical Engineer trying to source American parts. America just doesn't have the infrastructure for a lot of things you need. And even when it does, often you find China can do it better, faster, and cheaper. I can get a box of CNC machined parts for $10 each via 2 day DHL for a $200 shipping fee. An America shop would take just as long and charge me a couple hundred bucks for just one. And try finding some niche bearing on mcmaster-carr if you filter by USA, nearly the entire catalog disappears. A global supply chain is just the reality of mass producing machines these days. And imports can only have one Country of Origin so we can't be too detailed on the labels.
[1] https://www.anomie.tech/articles/making-hardware-in-the-US/