You're not answering the question - but just restating your conviction.
If I run a TOR exit Node because I think people should be able to access websites blocked by the Chinese government, people can still use it to send child-pornography. The agreement is only to use a certain kind of protocol - that is handling data in a formal way.

If you disagree with this than I would very much like to hear an explanation.
 
What is the implicit agreement every Bitcoin node accepted? Did you conduct a large survey of Bitcoin users to find out what they were 'implicitly' agreeing to? Who decided what kind of financial transactions were the appropriate kinds and what kinds of financial transactions are not?