The banning of Electron apps for using a non-public API just means it's consistent with any other application submitted to the app store... they cain't use them sweet private APIs neither. Users can totally still go and download a notarized application though and have no problems. It's something that'll very likely be remedied by the Electron team in its entirety if it hasn't already been...
As far as not giving a shit about Safari's ability to do WebRTC and PWAs properly; I don't really see that as Apple trying to kill web technology as much as them just not profiting off it. Apple doesn't make any money from the "web," they make it from their platforms which aren't HTML/JS/CSS. As a developer, that lack of focus does piss me off sometimes, but... as an end user I don't really notice. Safari is still the best mobile browser available, even if it is lagging behind the rest in terms of standards adoption.
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And tangentially, in my opinion, the Electron apps being booted is a good thing, if even only temporary, as I really hate downloading an app from the Mac App Store only to find its a full blow fucking Chrome instance for something that would be literally be two NSViewControllers and a handful of "slightly" customized views. Like "Yo, player, your system tray app to show this red or green icon is using 400mb of ram and occasionally locks my CPU. WHY!?!"