Yes, the humies were swimming in slime with cables protruding out of them, yes they could not do anything in the “real” world.
But look at the alternative: The “real” world was a barren wasteland, devoid of and hostile to life. Being “free” would have meant not bein free at all, because the dead environment would have restricted you from doing anything.
However in the Matrix, while still being restricted by the constraints of the simulation, it still had less restrictions on what you could do and you could do anything you like, certainly much more than outside.