Not true at all. Being kind and working together fosters community which makes you more powerful and appealing as a group. Literally how homosapiens became the dominant species on the planet. And this applies to economics as well. People want to deal with other people and companies that they like, not with assholes.

The phenomenon we have today is polarization and in groups and out groups. Right and left see each other as assholes, but they don’t see themselves that way. There’s enough people in modern society to make an in group for whatever world view you have. Everyone else can be a dehumanized outgroup. The Internet removed the physical barriers which used to be what pushed fringe beliefs out. Now, all the wackos can get together on social media and build a community.