One particular reason might be that HN has a lot of current and former Google employees on it, and they are pretty vocal and actively defend Google and downvote everything else - I have experienced this multiple times when bringing up anything negative about Chrome - which is really not that great of a browser. Especially the security (look at past number of patches) and memory usage is bad. I'm not sure why the community here speaks so highly about it.
[1] See "Adding support for native OS compositors to WebRender" on https://pcwalton.github.io/2018/12/07/plans-for-2019.html
Overall, still many reasons for people to be grumpy.
The main issue is still memory usage IMO. The way they implemented multiprocess browsing was to have a few long-lived processes rather than one per tab. Over time these processes tend to use a lot of memory, as scripts invariably seem to leak.
But, if I interpret the memes correctly Chrome isn't exactly frugal either.
Here is the tracking bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1386669