Your entire argument boils down to a no true Scotsman logical fallacy. ie: these people disagree with me therefore they are not Bitcoin developers.
A month old hastily made fork of Bitcoin Core which has not yet ever had a release (just lots of release candidates), unless I missed a recent announcement.
> who is in fact a Bitcoin developer and has been for a very long time.
Nonsense, Jeff hasn't been a Bitcoin developer for years. I believe he's mostly been involved with Ethereum for a long time.
People aren't saying he isn't a developer because they disagree, but because showing up and making a toy software fork doesn't grant you credibility or experience. ... and, in fact, he's shown that he doesn't have it pretty thoroughly, for example his code only managed to actually increase the blocksize a couple hours before his first release candidate because he completely misunderstood how it worked.