Some of the author's "reasons" are bogus:
"My code for Python 3.5 won't work with the Python 3.7 installation unless I intentionally port it to 3.7."
Sure it will, just invoke it using the Python 3.7 interpreter. I have plenty of code originally written with 3.5 that runs just fine under 3.7, 3.8, 3.9, ...
"In Python, you have to work to pass variables by value."
No, you don't. Python actually doesn't pass variables "by reference". It passes object pointers, but you can't "mutate" an object pointer; it will always point to the same object forever.
What this author doesn't seem to get is that in Python, "variables" aren't labels for memory locations; they're namespace bindings. And unless you explicitly use the global or nonlocal keyword, nothing you do with setting variables inside a function will affect the caller's namespace. Which means that, in effect, Python variables are passed "by value" to functions--the function can only work with the object it was passed, it can't mess with the namespace it was passed from.
What does often trip up new Python programmers is that if you pass a mutable object, like a list or a dict, to a function, the function can mutate the object (add items, remove items, change what object a key or an index refers to). But the claim the author is making is much broader than that.
"Calling the same object by different names doesn't change the object, so it is effectively global."
I think this person simply doesn't understand how Python works.
Recent counter example: if you have python code that uses the "U" open mode (e.g. open(file, "rU")), it doesn't work anymore with 3.11. Yes, it produced a deprecation warning for a few versions, but no, your script that works in python 3.x is not guaranteed to work in 3.y. There are plenty of other examples.