"let other people interpret it the way they want" I totally agree ... if art has a message and tries to teach or impose an opinon on other people, it can't really be an incentive or a source of new ideas and, as you said, it wouldn't work anyway
Mark Rothko said that in his paintings he was trying to provoke different emotions through the use and juxtaposition of colours. Pollock was creating a means of free expression or automatic writing using his art, he was very interested in how chance, coincidence and accident shaped the outcome of his art.