This letter could have been written any time over the last 95 years, so I don't think that we need to worry just yet, but, as you say, myths have a habit of sticking.
The writer forgets the AT and rotary fleets (AT as in Air Transport, not Adventure Training, and having a look at the RAF home page, an uninformed viewer could get the wrong idea). The writer fails to mention UCAS operated by the RAF...I could go on. The RAF Engagement team do work hard to keep gatekeepers and influencers (eg MPs) informed so I don't think there is too much to worry about the ill-informed rants of a retired Upper Yardsman (Supply).