I like making layouts even though they may take tens of hours. It's like sudoku puzzles for my mind. I need SID replacements and this project look promising. I previously considered the SwinSID project for a remake but non-working paddles killed it.
I don't like the sandwich style of the first SIDkick pico desing so I started a single board design. A more neat looking style. I have done such boards before.
In general, theres the differentiation between legally allowed and morally good. The work is under GPL and CC, so the allowance is out of the question * (see footnote). Morally, and especially if the changes are to the board layout "only" (in quotation marks, i know this is work too, the sidkick project even had the pcb design released under a different licence) one could have find NEATER (pun intended) solutions than a simple full fork "ripoff". Why not produce a cool nifty pcb that is in line with the "neat" style (i have the neat PLA in one of my 64s just for that reason) and release it as a single project. Maybe ask to merge it back to the sidkick repository.
Seeing that all of your repositories are 99% clones... you dont let a super bright light shine on yourself.
On the other hand, and this is where i will probably receive a lot of flak: releasing somthing under GPL and then "moaning" about shitty clone jobs (as meh as they are and as frustrating it has to be seing this sort of stuff) is also not morally clean. Like, you can't say "you can do whatever" and when someone does (even if its the most meh version of) "whatever" you get mad. Especially when the licence states:
"You may convey verbatim copies of the Program's source code as you
receive it, in any medium, provided ..."
I can understand the frustration and as stated, i dont see the move as morally good. But its exactly what you granted ppl to do.* (see footnote)
And using the fact that ppl are using the given licence rights as a reason to threat to move everything else closed source is also morally questionable. The "right" (as in: a probably better) way to go would be choosing a licence that forbits commercial usage.
*
Actually, is it? Its a bit unclear unfortunately what EXACTLY falls under the CC an what under the GPL. Is the schematic part of the pcb? If so you could not only not sell the derived neatkick for profit, even deriving a different version would void the licence!
Unless are reverse engineering everything from the publically pcb without any sources. And even this way would be kind of a gray area.
I didnt find the schematic on the git, only the link to the finished pcb. Either way, this again makes it MORE unmorally, as your only change is the hardware. And probably even a direct violation of the CC part of the licence.