Pretty lame, isn't it?
A few versions ago (probably 8.1.5 or 8.1.6) I tried to get around this. Oracle's install docs mentioned an environment variable you can set to have the install print *absolutely nothing*, taking all it's answers from a text file. This ought to work in all cases. Unfortunately, the installer still checked for the presence of an X server, even though it wasn't going to make use of it, and would stop if one wasn't found. I'll be very surprised if this has been fixed, but you might want to look at the official install docs and see if it's still documented.
Malte's right, VNC is the best way to do this. At least you are running Redhat 7.3 so you should alread have the X server installed. Until recently Redhat didn't include X in a server install because you don't need or want it on a server. Unless you're installing Oracle!