Well then, you understand why Trump Jr. would take the meeting. He might have heard information that the voters had a right to know. That's why I said it was his civic duty to hear the lawyer out. 

Politically it's the same thing. The idea is to win the election. So if someone offers information that could be damaging to your opponent, you take it. Whether or not you use it is up to you.

And yes, all that would apply to information about Trump or any other candidate.