that both positive and negative pressure are created in the pipe. It also said that the negative/pull side was what did the work. No question that you can create pressure, but you didn't clear the clog that way. It's the suction side that pulls the potato peels or whatever back so they can "redistribute" themselves and work their way down the pipe.
Proof--the fact that my plunger doesn't use a compression stroke but still clears the clogs.
Many professional plumbers supply stores do not sell those "can of compressed air" type drain clearing devices. They know that you blow P-traps and other sort of important parts off. They do have pressure rigs that operate in conjunction with rotary snakes to clear long distance clogs from tree roots and the like.