I wave to all Jeeps having descended from WWII GP, J8 and Willys. That includes CJ, YJ, TJ and even JK and LJ. That does not include the cherokee's, liberties, commanders et al, fine vehicles I'm sure, but not really Jeeps, IMHO.
When my '02 TJ got totalled and I was between Jeeps and relegated to a rental car my waving reflex was still active, but no one waved back, my wife said I needed a big 'Between Jeeps' sign on the windshield.
I've since been made whole by a '04 TJ and once again things are right with the world.
Now when other Jeep drivers fail to return the wave, I figure that'd be their problem and not mine. They're either distracted and/or not paying attention or are oblivious to their jeephood. In anycase, nonwavers are to be forgiven and/or pitied.
function over fashion is my motto