Ok when not glued: both magnets get pulled to each other. The hand has to use some force in order to stay in place, so the car moves.
When glued: both magnets still get pulled to each other, but now the force is cancelled out since the force that would pull it forward also has to be used to hold the other in place.
Lifehack for naive schoolchildren (i.imgflip.com)
Love and support (startrek.website)
Plus your enemy knows what's coming (startrek.website)