Jack doesn't go full-bore like the goat-goat-goats do, but he's not a lazy hockey player. His skating posture, however, straight-back with all power generation from his edges, especially while conserving energy for timely bursts, LOOKS incredibly lazy. This gets tolerated when we win hockey games, but if we lose, even if Jack's production gets better (see the ~15 games after the streak compared to the streak) it becomes the focal point of people's ire.
I wish Jack played with his hair on fire the way McDavid does, but his intensity level is no different from the greats who are just fine effort-wise. It's understandable to wish he was that much better.
And sometimes, yes, he needs to go harder, and isn't even "just fine." This is the case for all players, and only leads to calls to trade Jack because he's the captain of the titanic post-iceberg.
Maybe when we trade Jack and Sam, and have impeccable effort and locker room dynamics, we can accomplish our goal of looking like the tank teams we are desperately trying, and failing, to distance ourselves from.