That's very morally correct of you. Personally, I'd like respect to be on both sides of the relationship. I would rather not engage in a relationship (business or otherwise) where there is a high likelihood that someone will use psychological warfare in lieu of punctuated, professional, respectful language.

Respect for both sides is good and all, but if your opening shot is a contract like that, then at best you lack the basic respect of reading the contracts you send out, or more likely, have no respect whatsoever for anyone in the first place.

Given that, OP's email was exceeding any levels of respect merited by the messages sent to him.