Thats puzzling, because socialism is very easy to understand.
The bible states:
Mark 12, New King James
29 Jesus answered him, “The first of all the commandments is: ‘Hear, O Israel, the Lord our God, the Lord is one.
30 And you shall love the Lord your God with all your heart, with all your soul, with all your mind, and with all your strength.’ This is the first commandment.
31 And the second, like it, is this: ‘You shall love your neighbor as yourself.’ There is no other commandment greater than these.
The second law demands altruism. A society which is based on altruism is called socialism.
Atheists have come up with more worldly definitions. Like socialism is when nobody is held dependent and nobody is exploited.
Still this concept is important enough even for atheists that more secular definitions became necessary.
I dont get why any of this is hard to understand.