All humans are altruistic.
if communism made that fallacy it wouldn't have spawned so many authoritarian states. you're mistaking us for anarchists
Communist
ideology includes this fallacy, by assuming that everybody would work their asses off for the greater good of the whole community.
1. Why not
2. It's a matter of education and raising. Today, altruism is strongly disencouraged, due to capitalism.
1. What, are you living on the mountain top? Have you ever met some other people? This one is stronger, this one is dumber, this one can do this better, this one can't do a thing, etc.
Each time you're interacting with someone in any way more complex than talking about the weather, you're automatically assessing his/her worth. You wouldn't want to have a conversation with a dumbass. You wouldn't want to mess with a beefed-up guy. You wouldn't want to employ a complete loser. You wouldn't want to be led by someone without charisma.
Equality is fine as long as you're competing for a resource that everybody's literally swimming in - like air - otherwise people will use their abilities to claim the limited resources for themselves.
2. And I say it's a matter of evolutionary adaptation. As long as altruism is helping genes spread more than direct egoism, it's prefferable. What communists try to make us believe is that there can exist a permanent situation that makes altruism more efficient than egoism for everyone.