This is what we are always told. A man's ideas are separate from his personality and moral worth. But what if that's not entirely true? What if what a man thinks derives in large part from what he is? It seems clear that many of the ideas that have formed the modern world come from people with deeply flawed characters who may have formulated these ideas at least to an extent to justify their own flaws. Rousseau and Marx are obvious examples but there are many more, clever people led astray by their own cleverness and using it to avoid facing up to the reality of their sinful nature.
A good person loves the good. Or perhaps I should say someone who loves the good pursues the good and seeks to manifest it in his life. Someone who does not respond to the good in this way but suspects it may exist may seek to deny or belittle or even to corrupt it out of shame. The good is a hard thing to live up to. What is the good? The best definition I have come across is from Romano Guardini in his book The Last Things where he says that "in the last analysis, the good is God's holiness itself." Linking the good with God and holiness is very important for it goes to the origins of what the good actually is and what it should always tend to. All lesser goods crumble into dust when the base good is denied. A good person is someone who recognises this simple truth and seeks to live up to it. Obviously he will fall short but it is the intention, the motivation, that matters. A bad person is someone who denies it and who tries to substitute lesser goods, political, social, whatever, in its place.
What I am saying here is that if your heart is correctly orientated then your thoughts and beliefs should follow. If your heart is not orientated to the true good your thoughts and beliefs will reflect that misdirection. It is not true that what a man thinks bears no relation to what he is. Sometimes it is valid to play the man not the ball if you wish to understand ideas and where they come from.