I can't think of one point that counts as a demerit in python's case that you've been prepared to concede.
Here you have it. I am going to start a summary and expand on it.
Merits and demerits of Python:
Speed: Python imperative programming are slow. 50 times slower than C. (demerit)
Python can do very fast computations thanks to its libraries, such as numpy (merit)
Python has functional programming, faster than imperative programming (merit)
Code blocks and indentation Python uses colons and indentation to separate blocks.
This is a merit for some people and a demerit for others.
Easy of programming Python is very easy to program.
It is a good language to start learning programming. (merit)
This leads to a lot of code written by bad programmers. (demerit)
Code maintainabilityPython helps to make code easily maintainable in the long term. (merit)
Libraries Python has a large number of libraries (>300000).
Many for Artificial Intelligence, Big Data processing, Scientific, Web development. (merit)
Security issues relating the big number of libraries and dependencies (demerit)
Language updatesFrequent language updates that keep it up to date. (merit)
Frequent changes that are no longer compatible with previous versions (demerit)
Documentation and helpPython has many good free and paid manuals. (merit)
Python has a large, very active community of programmers from which help is readily available. (merit)
MultiplatformPython is multiplatform and runs on Unix, Windows and Mac. Recently in a web client as well. (merit)
Cross-platform libraries present certain problems (demerit)