Agree. When I see people make statements like "but they are not X" its almost always a value statement with a word substitution, and you can just swap in 'good' for 'creator' (or whatever other word used).
GP's opinion that management aren't 'creators' of course neglects a few things:
a) the role of management is necessarily one step removed from direct project output, so yes, they'll probably do less direct work on the project
b) that 'creators' can (and do) move in to management
c) there is no creativity involved in taking uncertain inputs and turning those into the direction & vision of a project
d) that shaping a project's output to maximize outcomes is something that can net a lot more value than adding another 'creator'
e) that 'creators' sometimes don't care about the project outcomes as much as the process
f) that 'creators' may not have experience in the various domains their product or service is ultimately being provided in, and thus may not understand or pick the right constraints to apply during their creative process.
...among many other possible misconceptions.
I've seen this in the education world myself, where teachers (who are similarly front-line workers) were skeptical of management and the viewpoints of those outside their domain being able to add value. 'But they're not educators' was the statement I heard a lot.