They don't always have that choice, or awareness of the consumer-side problems of DRM-protected content.

Exactly.

I can see how they may not have awareness, but in what way do they not have the choice?

What publisher you pick has implications for marketing, the share you receive, you're also not guaranteed to be accepted by your first choice.

That seems like a pretty mild trade-off. They're hardly going to be at the mercy of pirates on the basis of which publisher they pick.

Most authors want to write and be recognized, so they get picked up for more writing contracts. Piracy is really the publisher's problem.