In a small place like that, consensus must rule because the founders are basically equal. At a place like Microsoft, Oracle, Apple - the answer is that the big guys built the place and gave everyone their jobs so therefore they answer to them. Who are you? Some guy who just went through college and took no risk in joining some giant in their field. Who are they? The guys who took the risks to start those places. So if they think your ideas are shit, then they can say it and you have to take it. But at a company of 4 people, who are you? You are just a co founder of a (probably as of yet unprofitable) little startup company. Where are you getting the power to call their work shit from? Plus, if its a guy like that their time is extremely valuable and you are wasting it with your shit ideas.

I bet if you go into microsoft and sit in on the development meetings between a team on basically the same level on the org chart, they aren't nearly as hostile as top down reviews.