Spidey has super fast reflexes and can jump very far, or kick/punch really strong, but he isn't a speedster. He can't outrun a car for example. But he can move fast by making small jumps; small enough so gravity and air does not sap his momentum. That's why he is so deadly in an urban environment, but put him in a suburban one where buildings are sparse, and he is much less effective (anyone remember that old story where he trails a robber to suburbia and completely messes up everything?).
Now, that whole X-Men fight happened in a relatively small enclosed space. There he can keep bouncing from wall to ceiling to ground to wall at full speed, and rely on his spider sense to prevent him from making mistakes. His legs are strong enough to get him to jump faster than anyone could follow, and his reflexes are fast enough that he can keep fighting at that speed.
That's what it means for him to go MAXIMUM SPIDER. It's the same thing as how parkour runners can bounce around to climb walls and scale buildings, but it is magnified by a hundred.
So like he said, give him a little space, and he can take down anyone. He took down the X-men, he took down Titania in a solo fight (the same Titania who just beat She-hulk to near death), he fought the original x-men in their X-factor incarnation to a standstill while being so sick that he couldn't stand on his legs, he wore down Eric Masterson Thor, he beat fucking Firelord unconscious (even if it took half a day).