There are many science articles that I personally do not understand, most of them in fact. But I trust that as long as the methodology and findings can be studied, people who are specialized in that area will point out mistakes and try to disprove and improve each other. We don’t talk about phlogiston anymore, because science did its thing. I see free software in a similar way. As long as the source is free to study, and people are interested in finding errors, those errors can be fixed. Trusting software becomes more about trusting a community. It’s not perfect, but what is.