Idealism? No.
Anti-? No.
Spiritual? Another interesting question. The best answer is No, though I'd caution that "spiritual" admits of multiple definitions. The AOTC is spiritual-adjacent, however
Crackpot? If you presented the AOTC to random people on the street, most would agree with that descriptor. If you asked those with more specialised knowledge, some would certainly still agree; the majority would disagree with the AOTC without (I think) necessarily being so pejorative. I hope that helps. :)