How long have you had Bender? You said he didn't have a problem with people before? When did this start? Do you know anything about his history before you adopted him?
Sounds like he is nervous of people for some reason. That can happen with Chi's if they are not exposed to a lot of new situations and people or have dealt with abuse in their past. If in puppyhood he was left home a lot or not exposed to the world much, he would have picked up such emotions. It's common. Depending on how long you've had him and why he started displaying these fears, there are different things you can do. You need to start working with him with people and new situations - slowly, but consistently. Does he bark at people when they go by if he is on a leash, or in your arms?
Our Chi, we have had since a puppy. He travels with us and has been exposed to many different people and situations since a baby. However he still won't walk on a leash where there are people around. For example - if we are in a campground, he'll go potty on his leash, but he won't walk from the pet park to the camper - he has to be carried. If people approach him while he's on the ground on his leash, he gets scared unless he knows them. But if he's in my arms he feels perfectly secure and he doesn't growl or try to hide. This is common in small dogs too - just because of their size they can easily get intimidated - by people. Norman is very rarely intimidated by dogs - Chi's often think they are a lot larger than they are in reality. We have a Great Pyrenees and Spaniel so he's used to big dogs.
Anyway back on track - if he's not showing aggression at all, it sounds fear related, he's either afraid or just very nervous. Like I said reassure him it's OK for people to be around - carry him to get him used to it if you do not already. Let a stranger offer him a biscuit - or give him one when he does a good job of NOT barking at people passing by. I just think you need to work with him alittle - as long as he is showing no signs of aggression - when he growls is he snarling (showing all his teeth?) this is still completely fixable. Most Chi behavioral problems are fear related or due to something that has happened to them in the past. They can be quite insecure at times and need lots of reassurance from their person that everything is alright and they are safe.
I hope this helps a little - don't worry too much, I think it's perfectly fixable with some work.
