Because life - at least hear on earth - is pretty much made up by all kinds of bacteria and virus. So aliens might wipe us out, because their system can't hand

Because life - at least hear on earth - is pretty much made up by all kinds of bacteria and virus. So aliens might wipe us out, because their system can't handle it. But parent spoke about the right to fight, when we would attack, like ticks do attack us, like other parsites.