DC, maybe you are correct. However, I disagree with you about the compassion thing. Throughout the series, it seems that Tony and his crew could have more compassion for a horse than for whores - pun intended.

Even from the third season, we all knew that Tony would eventually find a good reason to kill Ralph because he deeply disliked him. The horse incident provided a good excuse and the timing was perfect: Ralph's jokes about Ginny allowed Tony to blame it on the NY crew. Don't forget that Tony, even when acting by his instincts, is much more calculating that he seems at first.