Unlike with iOS where it is easier for users to upgrade their OS if their phone supports it, Android version upgrades come most often when people upgrade their phone and that means at the end of a 2 year contract for most people.
Targeting the most recent Android version seems like a poor way to get people to use your app.
Note the: Targeting 4.1 and using the support package gives you full access to Fragments and Loaders while still supporting the older SDK versions.
Sure, if you target 4.1, you can't necessarily use every single new feature in Android on older devices. However, from a design/UI point of view, Android's backports of many new features (and projects like ActionBarSherlock) such as the action bar means you can design for 4.1 and have the code work with many previous versions.
I agree with the grandparent post: design for 4.1 and set 2.2 as a minimum. In cases where you want to use new APIs, you can use conditional classloading techniques.
Both you and the blog author are misunderstanding what targetting an API means. You can target 4.1 and still have your app run on 2.2 or lower. As others said, many of the new APIs have been backported to earlier versions. And targeting newer APIs have many additional benefits. As an Android Developer, you should always use the newest SDK and target the newest API. But still try to design for older versions.
The Android Support Package enables you to back-port apps written for the latest API level and using a Fragment-based UI implementation all the way back to Android 1.6.
Though looking at developer.android.com it does seem that it would be safe to target 2.3 as a minimum.
http://developer.android.com/about/dashboards/index.html
Unlike with iOS where it is easier for users to upgrade their OS if their phone supports it, Android version upgrades come most often when people upgrade their phone and that means at the end of a 2 year contract for most people.
Targeting the most recent Android version seems like a poor way to get people to use your app.