I agree with you in the sense that I think Clark learned in the most painful way possible that his choices have consequences, and that sometimes saving one person means he won't be able to save others--which is an absolutely essential lesson for a hero to learn. But even though Clark *feels* like he chose Lana over Jonathan, I don't think, in reality, he actually did--as Martha says, he couldn't have made that choice if it were presented to him that way. He chose to act rather than not act, when he had a chance to save someone he loved, and the choice had consequences he must reckon with--but I still wouldn't say it was his *fault* that Jonathan died.