> but if I want to find and filter some files nothing is easier to write than bash
That's like 10 lines in Python and much easier to read and test.
Look. We are working an professional field with a strong scientific foundation. There is no "this bridge is harder to drive over for me therefore I think it's bad architecture". The easiness and expressiveness depend on the problem you try to solve, not on the people, their tastes or their experience.
Shell tools are highly optimized to work in pipes, to work on files and to work on line separated entries like lines of code or lines of CSV. So if you have a problem where you need to pipe file handling into some filtering and into some line based transformations then you will have a hard time to find anything as easy or expressive as a bash script. And most projects on a unix-like operating system at least start like this: Understand the problem based on database dumps, logs, csv data measurements, previously written code etc.
If your regular expressions are not able to cover all the edge cases anymore and/or become unreadably complex then of course you should start an actual program. That only happens a few weeks into most topics though.
> doubly so when you need to throw more of them at this thing written by a former developer that thought he or she was saving money for the org by not spending an extra 30 minutes writing the program in Python or Go.
Yes, there are people who lack the skill or ambition to develop good code. We all hate when we need to deal with their stuff. But honestly, would they have written better code if they had used Python or Java or C++ for that problem? Unlikely.
A good coder would have some feeling for when he outsources some functionality to a python script. And if he develops a code base for a longer time most of his code will be in a real programming language. But even then it might be wrapped into a thin layer of bash to use find or grep or something that cleans up the input a little.
It's a single command in bash, invoking a program far more efficient than anything you can put together in python. It is literally a tool written for this exact purpose. I think it is simply ridiculous to not use a pre-existing tool that frankly you cannot out-do with a scripting language.
Even if you are writing a python script, you should _still_ use find to search for files if there is _any_ complexity in the search requirements.