Truth hurts. Always. It does not hurt as much when others tell it to you because you can deny it and pretend you don't care. The most painful moment comes when you realize the truth on your own, coming to the same conclusions without being forced. It is like embracing your own crown of thorns you've been putting on others for years. It hurts. It bleeds. It heals.
If there is one thing I managed to wrap my head around is that almost 99.99% of the cases it is a waste of energy to tell people they are wrong. You better let time build the mirror for those people who will eventually look at it one day. With the eyes wide open.

You know, now that you mentioned Mars. If we can't be friends with one of our own kind, I doubt we would ever come close to ever make friends with a martian in case one would ever have existed. Humanity has a history in killing, isolating or throwing prejudice towards everything it does not understand.