I had 20 good years supporting Manchester United but now I follow Arsenal, and I find the treatment of the magnificent Arsène Wenger by large sections of my fellow fans mystifying and depressing. I supported Manchester United because when Rupert Murdoch bought top-tier English football in the early 1990s and started marketing it aggressively at the middle classes — who, like me, had previously had no interest in the sport — United were the only logical choice.