I don't know where you're getting your information from, but it's just wrong, and you also misinterpreted my comment. Responding:
> Yes you can, and yes it is more-or-less trivial. With a small amount of deliberate practice, you can learn to produce a full and finely-gradated dynamic range on either a piano-weighted or a semi-weighted keybed. It's a one-dimensional mechanical skill that just isn't particularly difficult relative to, say, an oboeist's reed control or a violinist managing the very complex relationship between bow and string. If I say "you just don't press quite as hard" it'll sound like I'm being glib, but that's literally all there is to it, because physics.
Pretty much every piano teacher on the globe would like to have a word with you. The idea that it's a "one-dimensional mechanical skill" is greatly misleading when it has to do with joints in the fingers, wrist, elbow, shoulder, even your spine. Positions of all those things, varying degrees of muscle tension. And it's incredibly difficult -- pianists spend years improving their touch, and do things like Alexander lessons to eliminate muscle tension that interferes. "Don't press quite as hard" is incredibly complex, physiologically. (And oboeists are only playing one note at a time, violinists one or two -- pianists need to learn to independently control the force of all 10 fingers independently, sometimes all at once!)
But if you want to understand it in just a one-dimensional way, you can. Imagine that the full range of force a finger can produce is mapped from 0 to 100, and humans are sensitive to the degree they can adjust that by 1. Now imagine a weighted keyboard is responsive to the values between 10 and 60 -- that's 50 levels of sensitive gradation. An unweighted or semi-weighted keyboard is more like 25 to 35 -- merely 10 levels. Because we have so much less control, the software makes sure that the extremes are clipped -- you can't play as quietly or as loudly. Your dynamic expressiveness is severely limited. If you want to say "because physics", that's your "because physics".
You can measure this in MIDI outputs, actually. A good weighted keyboard will give you a wide range and an experienced pianist can consistently hit the same values without much noise. Whereas unweighted either gives you a much smaller range of values, or you can crank the output range up with software settings but discover that there's either a ton more signal noise because we don't have that fine control over our muscles, or else you discover that the intermediate MIDI values aren't even being used because the keyboard sensors don't support it (e.g. they only support 8 values).
> Pianists overwhelmingly prefer weighted keybeds out of habit, but more generalist keyboard players will often prefer a semi-weighted keybed for versatility. You can play gigs or sessions with either and you're the only one who's going to notice. Calling either choice wrong is just dogma.
That's false. Pianists don't prefer weighted out of habit, they prefer it because it's required for greater expressiveness, which classical/jazz requires.
The "more generalist" keyboard players you're referring to doing "gigs or sessions" are generlly not aiming for dynamic expressiveness -- they're part of a band or providing basic accompaniment to singers doing pop songs, and so forth. And that's fine -- unless it's Norah Jones-type music, you're not usually asking for much expressiveness from the piano in pop music. (She is much more jazz, after all.)
But that isn't "more generalist", it's pop. They're not practicing or performing Beethoven or Chopin, because it doesn't work except on a weighted keyboard. Nor are they doing jazz piano. You can't do it. Not well, anyways.
And you claim that "calling either choice wrong is just dogma", but that's wrong twice. First, I was very clear than there's nothing wrong with playing the synth. If you want to play synth music, I was clear that unweighted is great (you wouldn't even want weighted, actually). I specifically said weighted is necessary for classical and jazz. But second, it's not "dogma" that you need weighted for classical and jazz. It's just facts. It's "because physics", and the sensitivity of human physiology specifically. It's not dogma -- it's just reality. It's how the two instruments work.