Need Help. Pitch counts vs Taking Pitches!

I believe you must take into account also the batter. I watched a young man in a Varsity game on Friday evening swing at a 3-0 pitch. Our team was behind by a couple of runs. His batting average this year is very bad. He fouled off ball four and ended up swinging at another bad pitch on a 3-1 count and popping up. The next three hitters all singled and we only scored 1 run, whereas, he takes a walk we score more than one run in the inning.
Alot of times, we as coaches, have told the hitters 2-0 3-1 and so on are good hitting counts and that they must swing at THEIR pitch, that the hitter is so anxious to hit that they may swing at a bad pitch. I want my hitters to hit and hit it hard, but I also want them on base. And a walk will get you base and not hurt your batting average. But thats me, others may feel differently.