I've seen this about three times today, including once in my own comments and now here as well, an argument of the form "the theory that X may be wrong but it's still useful." That's like saying "this map may have the roads all wrong but we can still follow it" or "this restaurant is dangerously unsanitary but we can still eat at it." People should stop arguing like this. (Oh, and another theme that has come up several times recently (here, for example, is that of consultants giving presentations containing questionable or false information). Audiences need to demand more. Don't just keep repeating the same thing - if somebody rebuts it, you should take that seriously, as if it really was refuted or something. Or defend the original work with some argument of your own. But for goodness sakes, don't just say: well we know it's wrong but we can still use it.