this comic isn't funny... it's a father looking out for the welfare of his children.

Drowning children in ponds is another bad thing. Not dreadfully common, but fat tailed.

Cars were infrequent then, not a very common concern, and yet it was a scary possibility. Under 145k for the country of 87 million people, and that's counting trucks. 1907 was the year of the first drivers license in the US, and laws regulating driving weren't that numerous yet. The Model T came out in 1908.

It's hyperbole saying how bad church picnics are, not that they are *really* especially bad for kids but that they appear to be as bad. Hence the humor.

This is curmudgeon humor. Bierce and Mencken excelled at it.