I absolutely don't think that the current system means that the contents of journals are absolute truth -- I've been a referee and seen what happens to rejected

I absolutely don't think that the current system means that the contents of journals are absolute truth -- I've been a referee and seen what happens to rejected articles (they show up a month later in another journal). The point is not so much about the quality of what does come out, it's about the quality of the crap that currently does not come out. While I agree that it could be useful to have open discussions about papers, I think if that happens at the expense of the ability of everyone who thinks they have an idea to put stuff out there, the result might be a net decrease in signal/noise.