Zappos seems to stress a rock star image of it's executives and that it has a "family atmosphere". Meanwhile they pay low wages to their customer service and warehouse employees. It's really hard to believe they truly care while paying employees barely enough to stay afloat.
This is pretty typical of all call centers. Most employees bond together to create a "work family", while they while away the hours until they find something better.
The cynic in me says
(i) having "everyone, even the CEO" help out with customer support is a good motivational device to emphasise in what might in every other respect be a substandard customer support working environment
(ii) paying regular customer support staff at the low end of market rates is one way of recovering the imputed financial loss of having your $100/hour senior engineers and top bizdev staff focusing a part of their working year on basic customer support queries...
In my experience People don't dislike helping others, people dislike getting yelled at. No matter how good Zappos is, their CSRs will get yelled at, and I think everyone has a right to not enjoy getting yelled at, I sure don't enjoy it.