I regard lawns as bad because they are like concrete to most species and have very little benefit for wildlife. But are lawns bad, considering all the other activities and consumption patterns we urbanites partake in?
If kids and pets play on a lawn, it's especially important to make sure that the turf is organic so they're not exposed to the toxic chemical residues left behind by the products and service providers.
It's not just our health that suffers from our cultural obsession with lawn chemicals; our environment suffers too. The Chesapeake Bay suffers catastrophic "dead zones" resulting from the excessive nutrients running off suburban lawns.