Why Are Refillable Cups Only a Problem Now?

Most places will not allow you to fill refillable cups anymore

Out of an abundance of safety, places like Starbucks will not allow you to use refillable cups anymore due to the coronavirus pandemic. This brings up a great question: if it's unsanitary to do this now, why wasn't it unsanitary all these years prior? Have we just be passing germs back and forth out of the need/greed for seconds?

Here's another one that I've been wondering about. While handing your cup to someone and having them fill it and hand it back is considered a possibility for virus transmission, what about those people who drink out of a cup, then press it up against that little metal bar to get more? Wouldn't that also be germ heaven?

I've been working on not being such a germaphobe, but some of these things we do on the daily just don't make sense.