From the blog “Symantec recently highlighted Flash for having one of the worst security records in 2009. We also know first hand that Flash is the number one reason Macs crash. We have been working with Adobe to fix these problems, but they have persisted for several years now. We don’t want to reduce the reliability and security of our iPhones, iPods and iPads by adding Flash.“
Here is the discussion we had https://news.ycombinator.com/item?id=23654011