Arsenal threw their hard-earned lead away just before half-time against Liverpool today in a moment of complete defensive madness. The Gunners had dominated Liverpool in the opening 45 minutes before a moment of stupidity from their defenders and goalkeeper ensured things were level at half-time. For Arsenal and manager Mikel Arteta, it was the ultimate frustration. The moment came as all of David Raya, William Saliba and Gabriel got in a mess. And watching on for Premier League productions, former PL midfielder Andy Townsend felt that French defender Saliba should have done far better with de…