There's been Apple-bashing "feedback out on the net" since Apple was founded.

Most of it has been laughable. The stuff you're talking about is firmly within that laughable camp.

If Apple's QC were "crap" you'd see that in customer satisfaction ratings for their #1 product: the iPhone. But guess what? You don't see that. And there is no downward trend.

Shipping Mac OS so that anyone can just YOLO login as root?

https://www.macworld.co.uk/how-to/mac-software/how-stop-some...

Storing the full disk encryption password in plaintext on the disk?

https://support.apple.com/en-us/HT208168

How do you explain these except for atrocious and trending downwards QC?

I do not deny that those were both terrible, awful mistakes (and I'm upvoting you for correctly including them in this thread). I would note that they were both relating to what is (perhaps unfortunately, but them's the facts) a very minor product for Apple. And that they're both fixed. And that Apple's security overall is still unquestionably far superior to that of its competition. Ask anyone who has to administrate both Macs and PCs for a living (like me).

My comments above still stand.

Software, you could make a case, that's been a bit of a mess lately.

Hardware, though, you've got nothing. Where have they dropped the ball on their chips?

It's all one company. The reputation, stellar or tarnished, affects the entire brand. Their software QC has been bad lately, it's makes me question their hardware QC too. Those bugs/issues are often harder to find though - if they exist - they might not. But I think it's fair for me to question.

For a company that makes a large volume of a very narrow range of products they have a pretty good track record when it comes to physical hardware, and so far their chip work hasn't hit any major snags.

When Apple's custom CPU has its first F00F-type bug then we'll see how they handle a real issue.