I am leaning towards going to the interview because the starting pay is high and I've been out of aviation for a few years and this would be a good way to get a foot in the door.
However, I agree all of you. Them asking me to pay does seem unprofessional. I've worked in non-aviation industries and even the other industries would pay for out-of-state travel for interviews and they didn't have the luxury of ID90s, non-rev agreements, etc. with other airlines, etc.
If I had some other interviews setup that were close to matching the pay and benefits, I would not go to the interview.