The first thing to remember is that the Headwind or Tailwind designation for a Held designed javelin refers only to the point. Headwind and Tailwind shafts are identical but the Tailwind has a blunt point in an effort to combat some of the diving characteristics of the New Rule javelin in 1986. I knew when I deigned it that the Tailwind performed better than the Headwind in almost all situations. The exceptions were, extremely gusty days and when there was a strong tailwind behind a thrower who threw at very high angles.
Next, remember that the rules makers were not aerodynamic experts when they attempted to write a rule for the newly required veterans 700 gm implement. Consequently the 700 gram rule implement with a blunt or Tailwind point had the aerodynamic characteristics of a pre-1986 Custom III. It will not land consistently in a legal point first attitude unless it is thrown low and into a strong headwind. Most veteran throwers require a strong headwind in order to attain a high enough airspeed for a point first landing. This statement does not apply to top junior throwers in countries other than the USA who reach 80+ meters using 700 gm javelins.
Getting back to your question about the names contradicting the actions of these javelins. I originated the blunt pointed javelin for better lift under the new 1986 rules but none of the best throwers could be convinced to throw it at all. They all believed that the blunt point created too much drag. After arguing unsuccessfully for several months with the best throwers without convincing them, I finally said "Just throw the Tailwind when the wind is from the rear and there is less drag".
My tests all showed the tailwind point was best in both tailwind and headwind conditions but a javelin cannot be successful unless someone throws it.
The throwers began to call the blunt point implement a tailwind javelin and the name stuck. Later when Zelezny set a world record with it, Tom Petranoff called me from South Africa and put Jan on the line. He was kind enough to answer all my questions about javelin model and wind conditions. My final question was "Do you use a Tailwind under all wind conditions?" his answer was "yes" and he confirmed my beliefs as to the blunt point's suitability under all conditions. I should have changed the name of that model but it was too well recognized at that point.
I had this same usage problem with the Custom II and III in the 1970's. I designed and built that implement line in 1973 but no one used it until Bruce Kennedy tried and adopted it. It had been available for nine years when Tom Petranoff threw his first Custom III in competition. After that day, the Custom III was used all over the world. The actual javelin Tom used to set the world record in 1983 had a production date of 1974 under the grip. No one knew how to throw it until Tom showed them.