Some socialists hate Orwell. Some hate him because they like totalitarianism so long as they get to be the totalitarians. Some hate him because 1984 and Animal Farm have been used by capitalists as arguments against socialism rather than totalitarianism, but capitalists will spin anything to their benefit. And some hate him because they think he was an informant, no different than the people who gave names to the House Un-American Activities Committee.
Ask them about "Orwell's list", and they'll have few details. But there's a very good account of what happened in Orwell’s List by Timothy Garton Ash. I recommend it all, but if you're impatient, the short answer is "it's complicated" and the long answer boils down to "he shouldn't have done it, but he was lonely and a babe asked him to, and it was only about jobs for the IRD, which he supported as a tool for opposing Stalinism, and no one suffered from his list, and he shouldn't have done it, but he was lonely and a babe asked him to."
Was he anti-semitic and homophobic? Depends on what you mean by the words. Marx and Engels could be called anti-semitic and homophobic, but that has nothing to do with whether their work has value. When the argument against writers is that they weren't saints, the only proper response is an eyeroll.