Unlike ICO the IEO is not open to the public. You must be a hosting exchange user to participate in token sales.
It is not only this, but also requires you are huge investors to get advantages and invest in IEOs of good exchanges. Small investors are unable to join IEOs of good exchanges, believe me. However, I don't think reasons to feel upset if you can not join IEOs. You can observe and wait for good price to buy exchange coins of exchanges that you want to invest in their IEOs. Eventually, returns from capital is final objectives, IEOs or not, it does not a real matter; choosing good exchanges to invest is.