I'm conflicted; whilst ultimately you're right, it's very easy to type those words, and not as easy to test for a realistic load.
It's not as simple as throwing ab at your website, you need to use a proper tool (e.g. JMeter), make sure you're testing realistic user behaviour (even basics such as whether images and CSS have an impact), and ensure that you're not getting a false sense of security (e.g. how many connections are actually hitting the server at the same time?).
So yeah, whilst I kinda agree with you, I think it's a lot easier to say than to carry out.
of course, this requires at least some public traffic to play back. i've only used proprietary tools for this in my personal experience, but i believe jmeter has this functionality (log sampling).