It is an excellent explanation.
As to the original article, I would like to point out that there are quite a few people who feel that "inflation = theft", as the article also seems to imply. Especially hardline libertarians think so.
However, the price of bonds in the current period depends on expected future inflation. If I expect inflation to go up in the future, I will want to have a higher coupon bond. This is why a 30 year bond will, under almost all circumstances, have a higher coupon than a 10 year bond, which itself usually has a higher coupon than a 1 year bond or a 1 month bond (check, for example,
the US bonds (you can select the US from the drop-down menu)). Over longer periods, future inflation becomes less certain, and hence bonds with a long maturity have higher risk, and hence require a higher coupon (which is similar to interest) to entice people to hold them.
Of course, people may fail to take inflation into account. What's interesting is that if people were that irrational, then clearly the market system would not function well without regulation, and hence a libertarian utopia based on the market system would fail spectacularly. Thinking inflation = theft and thinking government (regulation) is bad and wanting to have completely free markets should be mutually exclusive. It shows how libertarianism is an ideology against government which lacks a logically consistent framework.