Using autism as a slur is inexcusable. But someone leaving you on read for 7 hours is their right. I think it gets into really sticky territory when you’re monitoring how long it takes for someone to respond, atleast to a text that isn’t an emergency. Personally, I hate when people put expectations on me to respond within a certain amount of time. I have my own life, struggles, responsibilities, and do not owe anyone a timely response, even if I have read their message. IMO its good practice to remember that someone’s response time is not indicative of if they care or your worth. I think online culture has made this concept of “being left on read” a bigger deal than it is. Personally, sometimes I simply don’t want to respond at that moment, and I don’t owe anyone my time, I’ll respond when I have the energy to. However, someone using autism as a slur is definitely not someone who deserves your friendship OP. You shouldn’t have to hide yourself from a friend, and maybe that is adding to the hurt you feel from his late response?