The socialist wrote the better warning of a book.
Actually, he was a left-libertarian.
Right. Why would a socialist write Animal Farm?
He was a socialist, not a communist. Animal Farm was written in opposition to Soviet-style communism and totalitarianism, not as some broad manifesto in favor of complete economic freedom. In fact, in 1946, he said "Every line of serious work that I have written since 1936 has been written, directly or indirectly, against totalitarianism and for democratic Socialism, as I understand it." This was from his essay "Why I Write".
Source:
http://www.netcharles.com/orwell/essays/whyiwrite.htm