This is an adorable counter point. It's like the religious saying that if you can't prove a higher power exists than it must exist. It's called logic and inference, and also because I am familiar with most of the other regularly parsing players, whether we're friends or I just know them by name. Typically a good player in a 'bad' guild will also have their damage suffer on progression due to kill speeds and the like, making the information from such logs generally irrelevant. I could really say so many things that make perfect logical sense as to why these logs are a poor source of information, but based on your responses I'm willing to bet you're not willing to accept them.
This statement couldn't be more wrong. In fact, if we're going by logs, you should take a look at any single target fight from any past tier. I guarantee the delta you see there, even among the top 20 players, instantly disproves this.
Not sure why people are still under the impression we're in Vanilla/TBC, but newsflash, we're not.