It's trivially easy to say "metric x is meaningless" if you assume the person interpreting it doesn't actually understand the context of that metric. You might as well say "metrics that aren't based on a solid understanding of your business model and user behavior are meaningless." Of course they are; this is not useful information.

If you run analytics on bad or incomplete information or information that doesn't realistically relate to something important to your bottom line, or if you try to interpret useful data without knowing what you should actually be looking at in the context of the service you're providing, it'll obviously be meaningless.