There's a difference between a tutorial and documentation? Who'd have thunk!
Actually, no there isn't. A tutorial is one type of documentation. Tutorials are documentation for processes. Non-process subjects require other approaches. It is important to write the right types of documentation based on the likely audience and the subject matter.
I disagree with many things in this article, not because the points are invalid, but because they conflate misuse of tools with low quality of tools. For example:
Wikis are great tools for writing documentation. They make it easy for people to fix minor errors when they notice them. They make it easy to collaborate on documentation without having to deal with the relatively high overhead of source code version control systems (which are particularly awful when merging structured content like XML and HTML).
What the author is complaining about is not the wiki, but rather the fact that those projects have no one who is responsible for maintaining the documentation. If no one is responsible for writing the docs and ensuring their completeness, the documentation will inevitably be half-finished, whether they use a wiki or some other mechanism. The wiki is not an alternative to writing documentation, but rather is a tool for creating documentation.
Doc generation software is great for writing reference documentation. By placing the content into the source code, it becomes the responsibility of the programmer to update any behavior changes when they modify the behavior of a function. It also means that the documentation for the function is easily readable right there in the source code when you're trying to understand a function. By producing the generated documentation, you then have a convenient reference for all your functions, methods, classes, data types, etc. that is readily searchable, indexable, and (perhaps most importantly) is viewed in a separate app or window from your source code so it doesn't force you out of your coding flow when you need to look something up.
Once again, what the author is complaining about is not the doc generation tool, but rather the fact that those projects have no one who is responsible for writing the documentation. When used properly, the output of doc generation tools is every bit as good as documentation produced by hand. However, it takes exactly as long to write that documentation in the source code as it does to write it in a word processor. It is not a tool for saving time, but rather a tool to aid in maintaining consistency between behavior and documentation.
To do software-generated documentation correctly, you need to add comments that explain every field in every data structure, every class, every function or method, and for particularly complex functions, even documentation for many of the local variables. You should write code in your build system to warn about undocumented methods and data structure fields. For example, in one project I regularly work on, there are almost 17,000 lines of documentation comments out of just shy of 59,000 total lines of code—a whopping 28.8% of the total code volume. The result is that it is fairly easy to learn what each piece does in the context of the code while you're looking at it, and the automatically generated documentation is pretty thoroughly fleshed out reference documentation for the project. One particularly complex class by itself produces a whopping 72 pages of reference documentation.
The problem that folks run into is that they usually don't put in any doc comments at all, or at best don't actually take the time to write the thorough comments that are needed to make the output from automatic reference documentation tools be useful. As a result, when you build the reference docs, you end up with an empty skeleton that isn't of much value at all. This is not a flaw in the tool; it is a flaw in the development team. They didn't take the time to write the documentation.
And so on.