I think this is a really bad look and blatant disregard of rules by the Red Sox. As a Red Sox fan I'm embarrassed and hope the team gets penalized. Can you explain this as justified to a child? I think no, they cheated, should be penalized and should apologize and take steps (only bright side is if this brings Farrell down, nice enough guy but boring and mediocre manager) to make sure it doesn't happen again. The other guys cheated too or it wasn't that bad, this and that happened before rivalry stuff is all rationalization.
The Sox fans shouldn't defend their behavior. I suspect most Sox fans like me are embarrassed, only the extreme are arguing or attacking. I'm sorry they did this, this type of behavior that has no place in sports and isn't sportsmanship. I want no part of owning or defending this, its a bad mistake.