It's pretty friendly, just depends where you ride.
I generally find the more serious / technical difficult the riding the more friendly the folk, the easier the riding, the more lycra that is present, the less friendlt people are... too much roadie attitude?
I ride at Mt Buller fairly often, probably becuase it's 3 hours from melbourne you only tend to get MTB enthusiasts, most people will say hello without prompting, most people will yell out and ask if you need help if the bikes upside down or the wheels off.
Lysterfeild, not so much.