In the physical world, people can and do take photos with you in it. They then get these developed, and may put them in an album with the people identified.
You would have absolutely no access to this photo unless they choose to share this with you, however that may be. They can also choose to share it with their friends, possibly even form a presentation with it to a certain slice of the public, and you still have no control over this, or even access to it.
This automatic re-sharing is quite the opposite, and I suspect Google did not fully follow the logical consequences through, or purposely chose to subvert the current physical-world situation. I don't like it, I'd rather have new-to-digital features following known physical traditions until there is ample evidence that it may be a good thing to change it.
In the real world, there is no publicly searchable meta-information of my name applied to the pictures you are talking about. Some relatives asking "oh who is that?" is very different than some Nigeria scam "African Prince" looking you up on google+ or suddenly finding a less-than-charming picture of you having become the latest "meme" but no your name is connected to it.
As far as getting access to the entire album, not everyone uses albums for the same reason. I can't, offhand, think of a situation where the rest of the album would make a difference, but it's not unreasonable to expect that one might want to share only parts of an album with some people.
If someone has photos of you and emails them to their friends you have no right nor expectation of notification. Maybe they might make rude comments behind your back. Not nice, but its a private conversation and they should be allowed to be rude in private.
On the other hand, if Google suddenly and unexpectedly makes my private photo album public just because I tag some people, that makes their service useless for non-public sharing of photos. I will therefore not use it and go back to sharing the photos by some other service.
The whole point of Google+ is that I can keep interaction with different circles separate. Unlike facebook I (thought I could) load photos that my friends would see but not my work colleagues. This sharing from tagging breaks that.
We are not talking about public albums. If you tag someone in a public album, then its fine to notify them. But for a private album making is effectively entirely public just because I tag one person is completely unacceptable. I have uploaded those photos with a reasonable expectation that they not be made public nor shared beyond the friends I want to share them with. If G+
Disclaimer: I have not tested whether or not this actually happens, so I'm taking the original article (and its comments) by their word. I do find it irritating though that anyone can apparently see the action of me tagging myself in a photo in my stream, regardless of the privacy settings of that photo.