No, that's not it. Model S and earlier just weren't built with racing in mind. They are only fast at straight line because they were only given HPs and Torques, which is only part of the battle. From what I've read, the chassis have never been stiff and I don't recall them having all the current expected bits of real performance vehicles, like locked differentials and such.
If people make those comments, it's because the cars weren't designed to compete in those scenarios, and there is just no way around that. Now, if that's what they're doing with Raven and Plaid, it's a different ballgame (article suggests the P100D sent to test may have stiffened anti-roll bar, among other things--but not that it does. So, not sure). The performance models are certainly bonkers off the line, so it's really just a matter of putting together an actual performance chassis and drivetrain that can handle the beatdown that extended track runs will do.
Fast in the corners > fast in a line on the Nurburgring. Torque isn't good for anything if the chassis can't keep you on line there and instead sends you into a concrete wall.