Well, the problem here is that you don't think he does anything at all to justify the statement. Everything you've said thus far leads one to believe that Vlasic just doesn't do anything right defensively when that isn't the case. Until you're willing to be receptive on the fact that there are things that Vlasic is equal to and/or better than Murray, you will always feel it's ridiculous.
The fact that you refuse to go into detail about it is actually a lot more telling than saying when he's good, he's good. That's a cop out from having to actually make a comparison between the two on skill sets.
It's not my fault if you can't properly make an argument and instead want to be completely abrasive about it.