Chewed out for having a heart!?!?!

So around mothers day my husband and I were heading into town to see my mom. We had a red and white border collie dog run out in front of us and we almost hit him. Lucky we were able to stop in time and he wasn't hit and made it across the road. Well I was driving home from work 2 days ago and I looked over and saw his rotting corpse on the side of the road. I was heart broken. So when I got home I got on Facebook and posted on my areas online yard sale sites that just about everyone in the community is on and told people about him. I thought the owners would want to know. Well my mom just text me and told me to stop talking about it on social media because her piece of shit boyfriend's piece of shit brother was the one that bit him and was having a hard time with it. 1. If he was having a hard time with it why didn't he call someone to let them know he hit the poor thing or do something to help the poor thing? He just left him there to rot! And 2. I don't care how hard it is for him, the owners have a right to know about their dog! And 3. Why would I care about that ass hats feelings when he has literally almost gotten my mother thrown in jail?! I hate him! He is a drug addict that does drugs around his little girl and doesn't take care of her and is a huge piece of crap that uses and abuses everyone! Just like her boyfriend!! I told my mom that I don't care the owners have a right to know and she said that I was being an ass to her and care about no one but myself?! Like ok? If I only cared about myself why would I be trying to find this poor dogs owners?! I'm so pissed and sick of being treated this way over having a heart and caring!! I did the right thing right??