python is not a bad language per se.
what people fail to realize is that each tool is suited for its task. python is good when you are doing data science or writing scripts. it sucks for everything else.
large scale development is virtually impossible in pure python. if you are writing an application, you are left with c++/java and such.
data analysis/ML/numerical packages rely on API written in Fortran/C. often, it would be just bindings that are provided to work in python, like in OpenCV and Tensorflow.
packages that are written in pure python will always suck ass. recently had to write software that used radon transform. scikit (python) took about 60x longer to run when compared to Matlab cause it was written in python and not Fortran/C like Matlab API.
people mostly hate python cause it's so popular and for many fags who don't code it's a buzzword like blockchain or AI.