People play lip service to hating hierarchy's but I would argue that they regularly espouse them and value them in almost all aspects of their lives. The ones they seem to hate are the faceless ones that they don't understand how they work, why they exist and who really runs them and has stakes in them.
People hate facelessness especially from those in power. But they are more than happy to take orders from someone they think they can relate to, see the hate for Obama or Hilary from the right but their love of anything Trump does.
As I mentioned, the exact reasons why people value hierarchies are IMHO not known. But people do value them, although differently. I recommend looking at the book The Authoritarians from Bob Altemeyer, which outlines the mindset of people who are Trump supporters.
There is also some research into universal values like Jonathan Haidt does, which shows that liberals value hierarchy less than conservatives. So people in fact do have somewhat different value systems.
Also, there was a fascinating story from Robert Sapolsky, which showed that in baboons, lack of strict hierarchy can actually benefit the group.
Personally, I am totally willing to take orders from my boss if I have good relationship with him, but I perceive it as helping a fellow human, I am not doing it out of respect to hierarchy. I think this can alternatively explain what you observe.
As I already stated, we have many possible explanations (and also perplexing examples) both pro and against hierarchies, but there is no clear unifying theory. The above is just a sampling.
