What is the ruling on speaking about Muslims or about people in society with disbelievers, and does this entail sin or disbelief?

The questioner is suffering from waswasah (whispers/obsessive thoughts). The cure for this is to completely disregard them, pay no attention to them, stop asking about them, and supplicate to Allah for healing. Merely speaking with disbelievers, even if it includes criticizing the actions of some Muslims, is not disbelief (kufr). As for speaking about communities or groups and reviling them, please refer to fatwas: 81889 and 145719. Regarding befriending a disbeliever, please refer to fatwa number: 94322.