The comparison between the tube and the parisian metro is either a joke or a big misfortune.
I really don't know where to start. I will not argue with you as you have your own opinion based on your experience.
I am sorry you have been robbed, but it is possible in all big cities, except in Japan and maybe some other countries. But your words say it is typical and I can assure you it is not. Friends have been robbed in Madrid, Rome, NYC.
Which lines did you use in Paris. Some lines are being upgraded with new trains and the RATP is finishing an important work in almost all metro stations in Paris. You cannot say it is dark places.

I will stop here as it would be too long otherwise.

I am really sorry you did not like your experience in Paris. But to be honnest, either you were unlucky, either you did not behave well.