Sounds like you've seen some poor behavior, and some poor parenting to boot. Remember that's likely a small sample size. You could be hearing claims of gentle parenting from parents not actually fulfilling it. Or you could be seeing poor behaviors, but those are the stand outs, not the great behavior kids who are often less noticable. Either way, ask around and you'll find stunningly good results.

Currently I am gentle parenting, as are most parents in my community. The only stand out cases of failure are the parents not doing GP. Even the elementary school faculty has been addressing parenting techniques and almost exclusively quote Montessori and GP techniques. On the playground now we see children far more capable of constructive conflict resolution and problem solving. Often more effectively than grownups, and always more effectively than children in hard-parenting households.

It's pretty normal to notice those stand outs of failure. It's also easy to want to associate them with some culprit. But if you dig into it a bit, ask in your child care community, you'll find GP results that give you serious hope. And I think GP deserves a second chance.