No, you're wrong. Any alliance can start up on any colour, people that have no ties to them are not responsible for their actions if they are stupid. Just by being on the same colour as someone does not mean you are supporting their actions. If you are allied by a treaty to someone then, yes, you are supporting their actions, but the act of simply being on the same colour as someone does not imply that you are supporting their actions.
That's like saying that because a murderer lives in the same town as you, you support the act of murder, even if you've never had any contact with that murderer before.