Answer:
Scrooge's unfriendliness was a result of constant fear.
Step-by-step explanation:
To put it shortly, Scrooge had felt abandoned and that abandonment pushed him over the edge. He tried to find comfort in his riches and wealth and, as a result, turned his back on all the poor people who managed to find hope and happiness in things other than money.
DISCLAIMER: This topic can be interpreted in many different ways, however, this is what I think the story is about.
Hope this answered your question! :)