For an actual answer to the DUmmy's revolting, hateful question, two reasons:
1. They're fellow human beings.
2. Love and trust are a two way street. If one group shows love and trust towards another, those things are more likely to be reciprocated.
To libs, it really is all about exploiting differences and turning people against each other over petty issues. They are, indeed, the real racists and bigots.