A lot of people like the idealized form of capitalism because it lets them keep the fruits of their labor, distributes resources where they are needed most, and raises people out of poverty. You have ancaps that are doing mental gymnastics to try and build a neofeudal utopia in their heads, but most people just like the parts of capitalism…. that are communist

Edit: also, ask them a lot of questions. Always good advice for convincing someone of something