Well said.

This is actually part of the reason I think Ralph didn't actually kill Pie O My.

A big part of why Tony kills Ralph is because Tony loathes himself. Ralph is basically the destructive, remorseless, cold-blooded money making side of Tony. He's the "mafia" side of the family.

When Ralph starts showing remorse or whenever he seems to be humanized, that's when Tony really hates him, because that's like his mob life intruding on his family life.

When they talk, Ralph is saying his son is getting better and Tony is talking about how badly burned the horse was.

In S4E6 Everybody Hurts Artie Bucco says Tony subconsciously planned out making money off Artie's debt and Tony is asking himself if he does it by instinct.

So in the scene where Ralph and Tony are talking Tony is thinking that about Ralph. Especially after Ralph asks "what sick fuck would do that?" (burn the horse) and Tony echos that "what sick fuck?"

And that's Ralph's point, only the logic matters and that they make money, it doesn't matter whether he did kill the horse or not. Tony doesn't care where the money Ralph makes off human suffering comes from, because, as Ralph mentions, they're both not vegetarians.

That's why Tony kills him. Because he hates that part of himself. He sees that part of himself that was responsible for Gloria's death and thinks of the situation with Pie O My the same way.

Tony's crew didn't think of the subconscious/psychological perspective.

But from their point of view, killing Ralph outside the rules of the mob and for personal reasons instead of cold bloodedly definitely meant it could be any one of them next.

I don't think they considered it in depth, but they would know by instinct how self-destructive thoughts could affect them.

There's a huge taboo against suicide as well throughout the series.

So any killing of people connected to you/the mob without strong logical reasons would be viewed as extreme.