There are a lot of reasons why mistakes happen, but for many reasons the startup stage is a good time to make mistakes.Especially before reaching critical mass, at least from a business perspective, I believe it's easier to justify upsetting a few thousand people if it means obtaining learnings which can impact tens or hundreds of thousands of the _right_ customers (and help you serve them better) down the road. I think the smartest startups are able to minimize their mistakes by practicing due dilligence and learning from others who have made similar mistakes.
Large, public corporations, in many ways, face a different set of challenges.They are expected to understand their target customer, deliver product(s), maintain revenue growth, all in the face of one other interesting challenge. When you take your company public, a core group of your customers changes roles from consumer to investor. Different customers have different needs and expect different things. Some need fault tolerance, some crave features, some need speed. Because you don't necessarily choose your 'investors' at this stage, there's no saying your expectations will be aligned.
One challenge of running a company is, not all 'ethical' strategies (such as apologizing, if it can be considered as such) result in either maximizing revenue or maximizing customer happiness. When you have millions of customers, I imagine every important decision can be construed as a mistake by some subset of customers.
We live in a Peter Pan world where many startups wants to stay young forever and never sacrifice their ideals. The truth is, a company is about serving customers well, making a promise, and delivering on it. In order to do that, you need to grow with your customer base and respond to the challenges this entails.
Special thanks to zephyrp for editing.