Is rubber cement in stationery stores the same as in tire patch kits? Is the rubber cement that you can buy at the stationery shop:



the same as what's in the little tubes of cement that come with your patch kit:



If not, then exactly what is different? What makes tire patches stick much more strongly?
The "cement" used in tire tube patch kits (de)vulcanizes the rubber in the patch and of the tube. Which is a chemical process, usually using sulfur, where the rubbers bond and form a stronger bond than just an adhesive would do.

Rubber cement is just a gooey adhesive. Usually latex with acetone and other chemicals to make it more pliant. You wouldn't want to use it to patch a tube since it is not very strong, will degrade the integrity of the surrounding rubber and patch, and in general make a mess.