It's not so much a personal insult as the common tendency most people have to base decisions on best rather than average performance. This essentially devolves to the Deming/TQM/Toyota/etc. school of management where you focus on making the system tolerate human error rather than hoping your humans consistently perform well.

That said, I do disagree that this is easily detected – I would bet that a significant percentage of C developers would not notice this if it wasn't mentioned in the context of a security problem. Linux kernel developers are [hopefully] well above average but … there's a reason why so many style guidelines feature this one prominently and it's not because few people have made this mistake.