Slime Block don't pulled by Ordinary Piston and can be pulled by Sticky Piston

Developers of Minecraft, did you guys forget the piston and sticky piston wasn't correct? Try place a slime block in front of both pistons and sticky piston you will observe it. (Left Blue, Sticky Piston and Right Red,Piston.) Is hard to say that the two pistons is slightly different in PC Version and Console Version. (not the exclusive in the piston.)