The polite thing to do is to take some time to research a subject if you don't understand. Not assume you're owed an explaination.
Could not disagree more. This kind of mindset will only push those who are generally unaccepting further away. When someone who is normally unaccepting extends an olive branch by asking "could someone explain this to me?" and you reply with "do it yourself" you think that person is actually going to look it up? My money is on that person doubling down on their original viewpoint.
Not that every person that wants an explanation is unaccepting...either way if acceptance is the future we want we gotta play this thing as a team sport