I tell people "drive safely", "be safe" or things like that when they're driving cars. Are you sure you're not being a bit over-sensitive?

And really, a bicycle IS less protective to its operator than a car is. It's not that bikes are particularly dangerous...but cars ARE particularly dangerous to cyclists. I got hit by one and was maimed for life...and I was "riding safe"--but that doesn't really stop someone else from swinging into oncoming traffic to make their left turn.