Where did I go wrong ?

Mirch, you're not accusing the other parents of being less sincere. This was neither mentioned nor implied in your post. Parents have differnt styles of parenting. And most parents do what they feel is right........and the rest of the responsibility lies with their kids. Your comment of "More Muslim than thou" reflects you how feel those parents view you. The central focus of your post is not to criticize the other parents' parenting........but to discuss their reaction to yours and the irony of it :)

If other parents don't feel comfortable having their kids in your home when your son has girls over............that's their personal opinion. If those parents choose to misunderstand you, so be it. You alone know your intentions and the true situation in your home. Your son is bringing the girls to the home where YOU can monitor him. Just because some kids don't bring classmates of the opposite gender to their homes doesn't mean that everything is going fine outside of the home. Just because an undesired behavior isn't taking place in front of a parent.......doesn't necessarily mean it can't take place behind their backs.

If those girls didn't come to your home to work on a school project............then those same girls would have worked with your son in school........perhaps in the classroom monitored by a teacher............or possibly even in the media center........where the librarian is not paying much attention to them.

You're trying your best to monitor your child. As a parent, you do what you feel is best for your kid because you're the one raising him. Not the other parents. And ultimately.......it's not the other parents to whom you'll be accountable to.

Just contintue your open communication and explain your views with reasons in the light of Islam to your child...to the best of your ability.