Yes, that's an important point. The Linux manpages are a joke, they're half useless almost all the time.
I don't know if this is common practice anymore...I don't remember the last time I saw a defective man page like this, but I still remember it with great anger. I love GNU, but I hate the kind of condescension it takes to try to force someone to use a different tool because you believe it to be superior to the standard tool (when it's really not; I find info pages to be obtuse to create, and difficult to read).
But we have other hypertext formats available. It'd be better if GNU started using some format that everybody already usees and knows how to write.
If you need a complex manual for a complex program, something is wrong.
I mean, the project wants to create an operating system that looks like UNIX, acts like UNIX, smells like UNIX, but from scratch with appropriate license that allows usage and access to source to anyone - so that the project doesn't get into legal trouble from whoever actually owns UNIX?
So drunk Stallman in 1981 says: "hik, let's call this, hik operhikating system GNU, hik, because it's not UNIX hik, but it sure looks like one, hik, but it's not, hik, but it kinda is hik, but it's not theirs hik it's everyone's hik". That's how I like to imagine it happened.
Now I no longer have anger management issues
The problem lies when you want to find something 1% of the time, and it's here that man pages become sprawling unindexed messes. For example, take a look at the man pages for perl or zsh: you'll have no chance finding anything, as those programs are so large that they need a wealth of documentation to go into them. At the same time, the info page for ls contains the things you rarely need to see such as exactly how things are sorted or the minute details of timestamp formatting. If this were all in the man page, you'd complain that you couldn't find anything in it.
1: My go-to example was always ifconfig, but linux's manpage for ip(8) really isn't that bad, as is actually the linux equivalent. Quality probably varies quite a bit based on the package that supplies the utility though, while OpenBSD's quality is fairly universal.