> why the fuck and how can Android phone and other embedded device makers get away with not publishing anything?
In general, the answer is that Linus Torvalds especially, and kernel developers in general, are very uninterested in filing copyright lawsuits, and it's them who have standing to bring a GPL violation lawsuit, rather than you as a purchaser -- it's not your rights that have been legally infringed, it's the code author's rights.
If the device manufacturer is not a US company (like the often-Chinese Android phone manufacturers), filing that lawsuit would be especially difficult even if the authors wanted to.
In these Sony and HP cases, they aren't required to put the source code on their firmware download pages. They're required to offer and produce it in response to a written request under GPLv2, or to instead bundle it with the hardware (e.g. on companion CD). You might find they actually do one of those two, since they're large US companies with mostly competent legal departments.
Incidentally, it took a lawsuit, or at least the imminent threat of one, for Tesla to start publishing kernel source: https://sfconservancy.org/blog/2018/may/18/tesla-incomplete-... . I think the lawsuit was primarily filed on behalf of Busybox authors rather than Linux authors.