If points are what you want then leave correct answers instead of commenting on incorrect answers. If Jon Skeet got points for all the deleted answers he left comments on he would have 600k instead of 300k reputation. I suspect he leaves those comments even though he doesn't get any points because he cares about the right answer.
But the point you make is valid: this Q&A reward system does not formally recognize the value of a critic who only finds fault with other answers. This is because the system already has an excellent self-policing mechanism: democratic voting for answers. If critical comments deserve reward then by the same logic a person voting for an excellent answer should receive credit for recognizing and emphasizing the correctness of the answer. But the voters just vote and the commenters just comment, to no direct benefit of their own.
A comment is low-risk. It cannot be downvoted, doesn't have to answer the question, it doesn't have to stand on its own. So leave critical comments if you wish, but realize that if you get what you are essentially asking for, your comment will also be deleted. If the possibility of that outcome bothers you, save your breath for praise and for your own questions and answers.