File a complaint with DOT.
[Essentially, you printed a bp (via OLCI), which Aeroflot said to do, but they instructed TSA not to accept them.]
Do they have check-in kiosks at T1? Could you have printed a bp from one of them--avoiding waiting in line to see an agent.
It's Aeroflot, the whole operation is a joke. I don't think all airlines understand the concept of paperless.
I flew Wizz Air for the first time this summer (NEVER again, the non-reclining seats actually are tipped slightly FORWARD causing massive back pain after the flight!) - they insisted on printing me a boarding pass when I checked in, telling me the mobile boarding passes often have trouble scanning at the gate.
What's. The. Point. Then? Oh, yeah, to avoid the boarding pass fee. They charge a few to print boarding passes. Except for when they insist on printing you one, for free, because they know their free boarding pass option causes problems.