He was 24-60 over the three years at Ravenwood(3-5 in post season play). His "good year" was a 15-18 record. He went 8-27 against non-district teams and 16-33 against a weak district 11AAA.
I think those could be some of the "reasons" you can't find. The Principal may very well be the monster described on this site, I don't know. But, she had all the reasons she needed to fire that coach. If you still doubt, have you considered his 9-36 record over the last two years at his new job?
If you think that is a fair reflection of the available talent at Centennial, I think you are part of the problem. Those girls need a coach not excuses.