When the author of the post says "
**Just** calling the big blind..." (emphasis is mine) he's referring to a strategy style where the only move some players make when opening the action is to call the big blind. I agree that it's a bad choice.
I don't believe he was stating, as you say, that someone should always raise or fold preflop. His use of the phrase
"...for the most part." was alluding to the idea that taking any action all of the time is a poor strategy choice.
Sometimes calling, sometimes raising, sometimes folding, depending on your opponents tendencies is best. How you balance those actions, giving preference to any one of them at any time, is what adjusting strategically is about. Your opponents aggression, positional awareness, and table dynamics will all guide your decision here.
In short, I believe you're assuming the author to have said something that he hasn't. It's still an interesting point though.
On the whole, choosing an agressive strategy (prediminantly betting & raising vs. calling) is vastly superior to a passive one considering the most common poker situations you'll be confronted with these days. It's a good place to start. You'll certainly need to progress from this point though.
So, I went through the article quickly and a couple of things stood out to me. The author says it himself, using a starting hand guide like this is if
"you haven't quite found your feet when it comes to starting hand selection yet." Experience will eventually dictate your decisions about the best actions to take, even if that actually is calling from the big blind all the time.
Also, the equity distribution of starting hands is NOT linear. The "Chen Formula" tries to equate for this weakness, but is less flexible than is best as hand strengths are relative, not absolute. For example, Many players think AA is just as much better than KK, as KK is better than QQ. It isn't. This graph illustrates that point...
The equity advantage of starting hands is exponential. Chens formula give more weight to Aces than to Kings, etc. but that will mean nothing on, for example, a four flush board with no card of that suit in your hand!
Good luck :)