Yes, there are those parents out there. As a teacher, I see kids who desperately need medication and therapy, and their parents refuse to provide it because they are in denial. They will even tell you that there is a history of mental & behavioral problems in their families, but their child "doesn't have a problem". It's always the school, other kids, teachers, etc.
Anyway, I would avoid this woman as much as possible. How you decide to raise your child is YOUR BUSINESS, not hers. And if she tries to tell you that you should try this or that, ask her point blank if she uses that behavioral/ discipline strategy. Chances are, she doesn't.
Let me give you a personal side to this. My sister believes that my son's problems are because of my bad parenting skills. According to her, my difficult child wouldn't need to be hospitalized or on medications if I were a better parent. She cited the fact that I haven't taken any parenting classes (and family therapy for the last 3+ years counts for nothing in her opinion) and that I don't set limits with my son.
The reality is that I chose my battles (see "The Explosive Child"), and I did try not putting him on medication. The result was being expelled from 3rd grade, and being asked to leave two private schools. The public school system has put him into a special, non-public school for kids with emotional and behavioral problems, and he's doing well.
Her kids are totally out of control. Her idea of "punishment" is to have them take a time out in their rooms, which are filled with toys. Her oldest is only eight weeks older than my son, and he's a narcissistic, selfish bully. While my sister believes that my son will be in prison some day, I KNOW her son will commit some white collar crime like embezzelment (he's already discussed how he would do it!). Her daughter, whose seven, just has to start crying and she gets whatever she wants. The three-year old twins are out of control, and my sister admits that she's "too lazy" to try and discipline them, much less potty train them. Does that sound like a "perfect parent" to you?
People who criticize are often insecure about their own abilities, so keep your chin up. The next time this lady says anything to you, change the subject or just tell her that you don't want to discuss your son's issues with her. Good luck!