I personally find the words from Apple to be misleading. It is not unusual for them to have such misleading advertisements about their products. For example, Mac originally required no anti-virus program, but now they apparently not not only recommend it but include built-in anti-malware protection in the OS. You can read more about that in our article on Internet Security for Mac computers.
Apple Safari is currently being advertised to block ads using Safari Reader, which is not true. Safari Reader in the Safari browser does not block ads as it states. It is not like the Opera browser, in which you can block ads by right-clicking the page or select the ads or visual distractions that you don't want to see.
Safari Reader will only load a stripped version of the webpage by removing unnecessary and/or necessary images. Ads are loaded still, when you view the page.
To block ads in Safari browser, you should use AdBlock for Safari that works like AdBlock Plus for Mozilla-based browsers such as Firefox, SeaMonkey and K-Meleon. You can also use a Hosts file for Mac that blocks malicious and annoying ads and websites.
Image credits: Apple Safari logo http://upload.wikimedia.org/wikipedia/commons/d/df/Web_Safari_Icon.png by Mikepanhu [GFDL (www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons. Screenshots taken by the author.