Its a human nature.. Not everyone can digest the feeling of being rejected without any resentment and that's the reason why they tend to point out the finger back to the one who rejected them. You've got to take things easily sometimes though it may seem weird in the beginning. Slowly but surely they will tend to sulk in the fact that they are rejected and that's the bitter truth, so they will become normal. They might end of becoming very good friends of yours. But this is not a general case as it does not apply to everyone, I am just trying to read the psychology of the minds of those who get rejected and become offensive.