I'm guessing that you think it's a bad thing but I don't quite understand your position.

Is it a new standard that if company develops code, they are morally required to seek "approval of the Linux open source community" ?

Are we applying this standard only to Google, or all companies?

If writing and open-sourcing code under permissive license is bad if it's done without "approval of Linux open source community", then how bad, in comparison, is what e.g. Apple or Microsoft do (not open sourcing iOS or Windows)?

As I interpreted it, that's not their position.

They're saying that if Google were to pursue their OS goals, specifically using Linux as a base, then they would likely end up doing things that would earn the scorn of the Linux community (at least; it's more likely that what they want to do is GPL-violating).

I don't think that comment was expressing a clear opinion either way, just stating that as long as Google is basing their software on Linux they are definitely legally obligated to follow certain rules (e.g., no direct linking of proprietary drivers provided by a vendor) and vaguely politically obligated to follow others (e.g., there's a fair bit of C++ in Magenta; adding C++ to a fork of Linux is technically straightforward but would upset people and also make it hard for patches to your fork to go upstream).

>but usually comes at the cost of performance.

Historically, with (ancient) 1st generation microkernels like Mach (used in OSX/IOS), sure.

Else, this article's decent: http://blog.darknedgy.net/technology/2016/01/01/0/

The other way we get separation is run multiple VMs under KVM which also has an overhead. The Microkernel arch that Linus never wanted is in fact, what we have right now. Exokernels and safe languages are necessity for getting having a good lifetime under battery power and having decent level of security.