That's because it's a tactic of the half-skilled AH aviator...a HOer is only skilled enough to get halfway to their opponents 6 o'clock. If you're happy with that skill set, play on. Don't expect others who try to fly well enough to saddle you up like hobo on a soup bowl to approve of that style of winning.
Personally, I could care less...as JUGgler always said, "there's way too much revenge in the hanger to worry about a skill less killer"
Please, by all means explain how someone flying an A5 with 20 and 30mm cannons is less skilled if they choose to head-on a P-51D (or, even better, a KI-43). The A5 has little worry of damage and a split second of hits will rip that 43 apart.
In fact, it makes so much sense to do so that the Germans actually used this tactic. It's all about strengths vs weaknesses and if your opponent has little chance of damaging you, while you have a much greater chance of downing them, why not?
Turning against a faster, more maneuverable aircraft is statistically less sound and in fact does not make sense to pursue when repeated head-on passes are on option.
Your statement doesn't hold up to an examination of history or to actual military combat tactics.
I'm not promoting head-on passes as a valid tactic 24/7, but they have a valid and useful application that most overlook because of their predisposition.
