I think, given that this is just some guy’s opinion (it’s not like this is someone who has a job as a professional copyeditor or publisher of a respected style guide), the only real takeaway most people should take from this is:
There are various conventions you can adopt around quoted punctuation
You, as an individual writer of English prose, have the option of adopting a style you prefer
It’s okay for reasonable people to disagree about that
Basically, all interpunction characters have started as "some guy's opinion".
All graphemes for the characters, too.
I know the "rules", but I've been also intentionally writing it in what I refer to as "functional style", e.g.:
"""
Greg's reaction was "But what of the otters?!".
Mary's "Nobody cares about otters!" was received with a stunned shock.
Joseph calmly said "I'm ambivalent.".
But Ophelia just "didn't care".
After hearing about the whole ordeal, Mary's brother was livid: "«Nobody cares about otters!»?! She's a bloody otterologist!"... and then he visibly shook, and his face blanked as he slowly collapsed into his armchair, looking broken, repeatingly mumbling to himself "Illogical... illogical...".
"""
First three are verbatim restated statements; fourth is a partial and/or summary statement (no quoted punctuation); fifth is a very complex example (and a long [but fully functional!] sentence.
We also need light-, mid-, heavy-strength commas. :p
There are various conventions you can adopt around quoted punctuation
You, as an individual writer of English prose, have the option of adopting a style you prefer
It’s okay for reasonable people to disagree about that