Surely the max tailwind speed is going to vary per aircraft and maybe even between types plus the company SOP. During training the good old PA28 had a 10kt tailwind component.
Airshow at Ohakea NZ many years ago, visiting US Airforce pilot was asked if they could still perform the same display if they had to change runways. Hell, he said, the F15 can handle a 50kt tailwind.
My understanding that the tailwind component factor was due to the extra speed the types were subjected to and the possibility of delamination due to this extra speed abuse. Sorry, no reference to back this up, just an article from a safety magazine that stuck in my mind.