Oh there can be plenty of bullshit in a small startup. When a company is small, there is very little place to move laterally to avoid dealing with people you find annoying. Especially if those annoying people have seniority over you by way of being in on the startup before you got in. They are unfireable and their ideas are held as gospel.

They can take the form of your manager, or colleague, or anybody in the company and the option is to either deal with it or bail on the company. In a larger company with many teams, you can usually route around such people by switching to a different org. Plus their power is often more constrained because there is just more people in the company.