I agree...let that one go in one ear and out the other.
You know your horse, you know how she's cared for, and you know how she's feeling day to day; you would be the first to know whether she would be up for a gallop one day. I hate when people presume to know they know your horse, when they've never even met it.
And then entire concept that a drafty isn't built to run? BS ... granted, they are far from the streamlined Thoroughbreds, Arabs, and other breeds that are known for speed and stamina, but to say a horse can't run just because he's big? Nonsense. Your horse would adapt to the wild just as easily as any other horse, because the instinct to run and be active is still there. Plus...those hooves could pummel just about any predator into the ground with one stomp!
Just enjoy your horse, and ignore the ignorant.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."