A: You didn't do it.

B: You hold no responsibility for what someone else did who was in the grave before your parents were even born.

C: In broad strokes things are getting better. Numerous massively destructive diseases effectively don't exist except for self absorbed anti-vaxers who think small pox is better than a perceived risk of autism citing a causal link that doesn't actually exist. War's have been reasonably small for the better part of a century at this point. It's broadly accepted that humans hold equal rights and no major country considers the concept of slavery.