[magduf]

Mine don't, and my car is pretty new. The problem is: I leave my wipers on almost all the time, rain or shine. With automatic wipers, there's little reason to turn them off, so I end up just leaving them on most of the time, and then when I get splashed by a passing vehicle going through a puddle or something, the wipers will automatically clear the windshield.

You wouldn't want the headlights to turn on all the time when wipers are on automatic mode. Now why they don't turn on for regular modes, I'm not sure, but probably consistency: if you don't turn them on for automatic mode, but you do for regular mode, then that's going to be too confusing for the driver. Maybe they should come on when the wipers are activated in any mode and stay on for a certain number of seconds (by "stay on", I mean actively clearing the windshield, not just waiting for water to appear). But this might be too unreliable in practice?