If you are at the gym, do you wave at the other people on tread mills? Do you get upset if they don't wave back?
On a usual ride, I have no clue how many cyclists, cars, pedestrians, or squirrels I pass. If I notice someone, I acknowledge them, but more often than not, I don't even notice them.
As to clothes, do you wear your street clothes in the swimming pool, or do you put on something that may be revealing but is designed for the task? Cycling clothes are performance clothing for a performance sport, no different than a baseball uniform (those are Capri's, you know) or yoga pants (when actually doing yoga). Sure, you can ride 150 miles bareback in cut off Levi's. You are much cooler that way, with a hole wore through your scrotum, than wearing something specific to the activity.