Today I read the article on molestation of young girls by teachers in maktabs.

Answer

Yes, respond to their Salaam. It is possible that they have made Taubah. Don't mull over their evil deeds. Keep your focus on your own deeds. You will have many sins and skeletons in the cupboard to reflect on. The purpose of exposing such persons is for people to beware and to be on guard. It is not to despise sinners. Never despise anyone, regardless of the notoriety of his/her sins. Yes, be kind to them, and always bear in mind that: "I am lower than a dog."