From TDN:

“Our regulation of corticosteroids is really based on racing safety and equine safety. When I think of performance enhancing drugs, I think of EPO, doping, amphetamines, that sort of thing. The classic hop that we talk about. Whereas corticosteroids could allow a horse that is unsound to feel better and race better than he otherwise would. And so, that’s a safety and welfare concern. I don’t consider that to be a performance enhancing problem”.

She also says Baffert’s explanation is “plausible”, and that she uses that stuff on her own dogs.