I don’t know about the readers, but I always used secure anyway. You can still move back to http, but that would be very unjustified.
Google was concerned about latency issues caused with https, that’s why it was never defaulted, but now Google seems to learn that security it the topmost thing we need.
Definitely this is triggered by High profile attack on Google from China. Google may leave china forever leaving a message for it’s worldwide users: “Security is our top most concern”.