I have yet to meet a (academic) researcher that doesn't like to talk about their research topic if somebody comes and is genuinely interested. I mean most work on a topic that has maybe another 10-100 people in the world who are interested.

The problem is that instead most people to come to them are either obvious crackpots, who think they have solved cancer (energy...) and contact the person because they are a biologist, physicist ... (on a completely unrelated topic usually). Or they come from a place of arrogance, i.e. "we do ... like this, our method is clearly superior you should adopt it", or even worse here buy our clearly superior method.