I've had conversations with 'leftists' who religiously ignore right wing literature and are shocked to hear me cite it after revealing that I'm a Marxist. Concrete analysis of concrete conditions and the ruthless criticism of all that exists mfs. That means you've got to learn to read things you disagree with.
You can't treat it like a team sport where you assume that your side has a monopoly on knowledge (well, MLs do, but that's different 😉) or as if contrary views are contagious. If you're at risk of reading a biography of Reagan and becoming a neoliberal, perhaps you're not as principled as you'd like to think.