He had but one eye, a feeble one, and his legs were not to be depended upon; but he managed to cover a great deal of ground, to have many painful little adventures, and to get monstrously hungry and thirsty before he happened to look in upon Penrod and Sam.
When the two boys chased him up the alley they had no intention to cause pain; they had no intention at all.

They were no more cruel than Duke, Penrod's little old dog, who followed his own instincts, and, making his appearance hastily through a hole in the back fence, joined the pursuit with sound and fury.

A boy will nearly always run after anything that is running, and his first impulse is to throw a stone at it.

This is a survival of primeval man, who must take every chance to get his dinner.
So, when Penrod and Sam drove the hapless Whitey up the alley, they were really responding to an impulse thousands and thousands of years old--an impulse founded upon the primordial observation that whatever runs is likely to prove edible.

Penrod and Sam were not "bad"; they were never that.