I don't like it when people say "transit dependent" to refer to people who don't own cars. Dependence implies that someone isn't pulling their weight, that they're taking something from society without giving anything back. That's not the right way to label people who don't use their own car.
I think transit riders are "transit interdependent". Yes, they depend on transit for mobility, but transit also depends on them. Without transit riders, transit wouldn't have a political justification, and transit fares are a critical source of transit revenue.
Now, most urban transit systems are subsidized, but highways are subsidized as well. Gas taxes don't cover the whole cost. When the auto industry fails, the government bails it out. Wars are fought for middle eastern oil at massive public cost. So why are we labeling transit riders as "dependent" instead of drivers?
"Transit interdependent" makes sense for another reason as well. Society depends on transit, to help those unable to drive, to reduce traffic, to reduce pollution (if enough people use it), to save land in a city otherwise wasted for roads and parking, and to provide living-wage jobs. Likewise, transit depends on society for financial support, for riders and for appropriately dense land uses to support the transit system.
Transit riders are not "dependent", we're "interdependent".