LKML has always been a pit. In 2001 already, it was assumed that posting on it as a new contributor would involve surviving a barrage of sneer and abuse. Part of it was just the culture around C communities since at least the early '90s, "l33t h4x0rz" and all that; part was Torvalds himself enjoying the occasional public humiliation a bit too much. It's probably much worse now that there is big money at stake.

As for maintainers "taking and rewriting", that has happened since the beginning of free software, the tales of "XXX took my patch and rewrote it, without crediting me in any way" are legion. It's why "Reported-By" was belatedly added, because the phenomenon is so endemic that doing nothing looks bad. But it still happens every day in all sorts of projects, not just Linux.