Facebook decided that the bug has no priority and changed the status to "Won't Fix" at December 7th, 2013.
The original bug report was marked as a duplicate of https://developers.facebook.com/x/bugs/309157325894924/. See this page for more info.
I think this is a shame and I would still like to urge anyone who thinks the same to open a new bugreport for the issue. Or leave a comment on the report stated above. Since this seems to be the only way to create some sense of urgency for solving this problem.
PS: I recommend a bugreport since my comments were deleted lately.
PS2: Even my bugreport "to state the won't fix issue in the documentation" seems to be ignored. So every day new people will research the possibilities of a mobile web app with a connection to facebook and will wrongly assume they can use the "facebook friend dialog" in their web app on mobile devices. My hope is that they will find this page during their research, and steer clear off that assumption.