It's not just kids that live on farms. Pet owners and those that keep somewhat less clean homes also have fewer allergies.
We will likely not see a 3rd world transplant carrying a "superbug," at least not by the current definition. MRSA (and the like) are products of inefficient antibiotic use and lateral gene transfer between bacteria. You get that in hospitals where there are lots of antibiotics and lots of people living with "routine" bacterial infections. You don't get that where there are few bacteria and people dying from "routine" bacterial infections.
Molecule for molecule, the human body contains orders of magnitude more bacterial DNA than it does human DNA...
But, epidemiology studies like these are important. Guffaw at the study but then lift the toilet seat with your boot? WTF. A little E. coli is no big deal, right? Those ultra powerful hand dryer manufacturers sell their machines as eco friendly and more sanitary. A towel dispenser doesn't use any electricity, and may spread fewer bacteria. These studies can also help track the spread, or source, of an outbreak. They can also be used in sociological studies (like what factors affect hand washing in public restrooms- the number 1 factor is the presence of another person...).
Mike Rowe (the face of Dirty Jobs himself) is an admitted bacteriaphobe and did an entire episode on how dirty hotel rooms are- bedspreads, phones, and tv remotes in particular. I bet he uses air blown hand dryers.
But, to the "funny" poo flinging hand dryer. Be honest. What do you use most? Paper towels or the hand dryers? Most people gravitate to the tech- it must be better. Now, imagine this tech in a hospital setting. A little E. coli may be no big deal, but now imagine that hand dryer arisolizing MRSA...
For myself, I am also in the camp of papers towels to dry and open bathroom doors, or push it open with a foot or elbow. But, I try not to get wrapped around the axle about this stuff. One thing from when I was a kid sticks in my mind, "God made dirt. Dirt don't hurt..."