That's not true. Most people are interested in fostering a community, even when it means sacrifice.

There _have_ however been studies that show that this attitude is prevalent in (neoclassical) economics students and others who are exposed to (neoclassical) economic thinking: https://www.sciencedirect.com/science/article/abs/pii/S22148...

It's very effective propaganda. And we have a good example of it here. (Mot saying you're spreading it maliciously, but you are spreading it).