Who opposed Plato's views?
Though Aristotle was a student of Plato, they were opposed on several views. Though Aristotle was influenced by Plato, they did take opposing sides to several matters. For example Plato believed that what the world experienced through senses was real. Aristotle believed that knowledge through senses was unreliable and couldn't be real.
It means exactly what it sounds like: perspectives that are opposed to Jews and Judaism. Most often, these views are not just opposed to Jewish positive interests (such as Zionism and the State of Israel) but are opposed to Jewish neutral interests (such as the right to live as equals in society) and anti-negative interests (such as freedom from fear of violence and attacks).