On the surface by stories related that certainly appears to be the case.
However we don't have any data (only anecdotes) on how many patents are pursued this way that are actually valid. And 'back in the old days' it used to be that you could have an actual patent and then get shafted by some large corporation simply because they could afford lawyers and you couldn't (meaning 'mr small inventor')
What I am saying in no way means I don't think there is probably abuse (there are enough anecdotes to think 'something is wrong here') but really we need the entire picture and dataset to decide that (in all fairness).