Regardless of confidentiality issues, the post was definitely in poor taste. For example, he talks about "android’s less-than-beautiful UI". If I ever hired a contractor, and he posted something to that effect about one of my products, you can bet I'd never hire him again. It's extremely unprofessional, and a breach of trust. It's one thing talking about this stuff between friends, but another to badmouth your (former) employer to the public internet.