As someone with a (healthy?) distrust of the content I copy/paste, and would never run code I copy/pasted without checking it first (one of the examples given in the linked bug report thread), I would still rather my browser only copy the text that I visibly highlighted. It is annoying to edit content out that I have carefully selected.
Absolutely. But how do we solve that problem and still allow proper usage of it? Removing this feature would break the copy ability of nearly every rich-text-like web-based UI in existence, such as Google Sheets.
Personally, this feels more like something for an adblock-like addon.
Why that is a hard question can be understood by reading through the discussions in the OP.
Skipping over the technical implementation issues, I'd rather copying rich-text-like be relegated to a "Copy Rich Content" context menu action, and the default copy command be plain text only.
I very seldom want to copy rich content. I very frequently am copy/pasting content to notepad, selecting it, and then copying it again in order to strip out the rich content I don't want.