seeking deeper (language theory) reason behind Python design choice

[Python]

On Tue, May 15, 2018 at 12:52:42AM +0000, Steven D'Aprano wrote:
> But you miss the point that even if = versus == errors are picked up by 
> code reviews or tests, they are still software bugs. Your *process* 
> (testing and reviews) picked up the bug before they went into production, 
> but *the bug still was made*.

I do not miss this point.  My premise from the beginning was that
humans make mistakes, this bug will occur, and most importantly it's
no worse than any other bug.  Wrong code is wrong code.  YOU'RE GOING
TO SCREW UP, and you need *SOMETHING* in place to catch that.  It may
as well also catch this, and it's NOT that hard to do... If you had no
other tools, you could write a regex to scan your code for it and
review the matches.  If you never discovered that this was a
well-known pitfall that's one thing, but I've known about it since
approximately 1986--it's been around a long time as you yourself say,
so there's no excuse for someone now, 30+ years later, not knowing
about it and watching out for it... unless they simply don't care
about writing working code and so put no effort into learning about
such things.

The noob argument only reinforces my point--they're going to screw up
all manner of things, until they learn not to...  The noob argument is
only a worse example of the same reason why we have software
development process (and mentors).  If you're in the unfortunate
position you described, where you don't have peer review, then you
need to employ good proccess EVEN MORE, because you have only yourself
to rely on.  If you don't employ it, it's pretty much a guanrantee
that your software quality will be sub par, unless you are a true
superstar.  [They exist, I've come to know a small handful.
Unfortunately I am not one of them.]

Seperately, I asserted that you can, if you really want to, learn to
not make this mistake, BUT IT'S NOT RELEVANT TO MY POINT.  In life we
learn to stop making all manner of mistakes, and reduce the frequency
of others.  In nearly half a century of life, I've NEVER made the
mistake of putting my hand on a hot stove burner, because I've learned
that it's dangerous, and take extra care around hot stove burners.  To
me this bug is exactly the same.  Likewise I'm POSITIVE there are
types of mistakes that YOU never make, though this bug may not be one
of them.  I'm certain it can be one that you learn to not make, if you
exert the required effort, whatever it may be *for you*.  But I must
admit that neither of us can conclusively prove the other wrong, and
you will likely believe whatever you've convinced yourself of already,
just as I do, and that's fine.