On the contrary, it made it far more difficult to understand the program since you had to know which method was called in which object due to polymorphism when you looked at the code. You had to jump around like crazy to see what code was actually running.
I agree with this point, but polymorphism is often the better alternative.
Using switch statements for the same thing still have the problem that you need to jump around like crazy just to find where the variable was once set. It also tends to make the code more bloated.
Same with using function references, except this time it can be any function in the entire program.
The solution is to only use polymorphism when it’s absolutely needed. In my experience, those cases are actually quite rare. You don’t need to use it everywhere.