The Spanish Flu killed more Americans in 1918 than the First World War. Movie production and theaters were shut down. So this cartoon about how Bobby's dog Fido is thought to have the Flu is about the equivalent of an episode of "Spongebob Squarepants" in which Squidward deals with 9/11 in 2002. Ain't gonna happen in a kiddy show.
This was the Teens and while children were considered an audience for cartoons, adults liked them too. Also, people didn't worry about traumatizing their precious little snow flakes quite as much.
That said, this Bobby Bumps cartoon is, like most of them, a little thin in the matter of plot points and gags. It was still early days for movie cartoons -- this was the year that the Fleischers invented Ko-ko the Clown and Pat Sullivan turned out a cartoon about a cat. So if you want to see what they were up against, this is a cartoon for you.