I've never seen the problem with facing bad bowling in the nets. You have to face bad bowling in the game, so why not practice against it? No point grooving yourself against 80mph back of a length stuff from the bowling machine if all you face in games is 50mph loopers than hold up in the breeze.
It amazes me how many batsmen are competent against good bowling, but as soon as someone slow or erratic comes along, they lose their gameplan and take a huge slog or chip one straight to cover. Do you ever practice against bad bowlers? you ask. "No", they reply.
There's actually quite a skill to being able to efficiently put away bad bowling without going berserk or taking on too much risk.