Widely misunderstood
People who don't understand the jump between the kid that smelt odd and the banning obviously missed the whole point of the cartoon: That's how probition works in REAL LIFE. Blame is totally placed on something it had nothing to do with and the authorities ban it, as though that would solve the problem.
Prohibition of drugs comes to mind. Back in the 1930s, marijuana was a relatively new drug in the United States (though it had been used elsewhere in the world for thousands of years) used mostly by minorities. The government was racist and wanted a way to put minorities in prison, so they spread racist propaganda claiming that smoking marijuana "made black men look lustfully at white women," among other things, and so it was banned.
There was obviously not a connection between marijuana and interracial lust, nor was the latter undesirable. The problem was simply the people themselves, and their own prejudice.
In the same way, the advertisements they banned had nothing to do with the kid being set on fire- it was his fault for being covered in petrol, and the other students for waving a sparkler around him. Banning was a totally mismatched solution to the problem.