Unfortunately this is how from the moment we are being taught.
Because it is much easier and convenient to teach! By teaching
polarity and attaching emotional labels such as "good" and "bad",
as a child, we do not really judge, we are taught how to react with
attachment of rewards for "good'" and punishment for "bad"
behaviour.
Rewards may as simple as lavishing affection or physical rewards
and punishment may be corporal punishment, restriction of
privileges or simply withdraw of love and concern.
As a child in most cases world view is neutral, with good and
bad learned as one gets older. As life gets more complicated, very
good and very bad added later on.
Everything is in relation to "I" and "us".