I admire you for what you did! So many people would have just passed on by. I would surely have been in serious trouble because I have a problem keeping my mouth shut. I would have blasted those boys and probably needed an ambulance for myself! I know that would not have been the proper way to handle it but my patience is very short in certain situations. I'm so glad you handled things in just the right way.
Your son might be upset now but he will look back on these days as he grows and will have wonderful memories of his mothers kindness.
That was a wonderful thing you did for that poor kitty. You are now my HERO!!!!