These animals get taunted every day. How many fathers have put their little one on the railing so they can see better.
At least you have to admit that you don't know exactly what acts of taunting these boys were committing.
You can infer that it was bad enough that they immediately knew they needed a pact of silence, even though there was great pressure on them to give information.
So they MUST have been doing something pretty bad, far beyond the example of father-child that you offered.
Before you absolve the boys, you ought to be a bit more curious about what they did to provoke the attack.