Life is too short to get all worked up about this. If someone makes an offer that is below what you will accept, all you need to do is reject it. If you do so politely, you may find they come back with an offer you find acceptable. That's exactly what happened to me, when I sold my SACD player.
I've had my own consulting business now for over 18 years and after I've gone back and forth for some potential gigs, I get this "one sided" contract offered for my autograph, instead of getting my undies in a bunch, just let them know that they'll need to strike that language, or I won't accept the contract...on a number of occasions have turned down work, because I don't want to deal with people like that.
Move on to the next one!