We (Indians) should email German authorities and express our frustrations. If enough people do it, it is bound to make a difference.
Please modify/customize and send this email (or something similar) to your local German Consulate General. You will find the information and email IDs at:
https://www.immihelp.com/usa-transit-visa-experiences/12/
Dear Consul General:
Until recently, citizens of India working or studying in the USA (with a valid US visa) did not require transit visas to connect to other flights at the Frankfurt and other German international airports. We are now being told that we need transit visas even if we are just connecting to other flights and not leaving the airport terminal in German airports.
If this is true, this can cause tremendous hardship to travelers who are just transiting via Germany. As you are aware, it takes time and money to obtain visas, and it is difficult to do get visas every time one needs to transit via Germany (for frequent flyers this can be a real problem). Many of us (in the Indian community in the USA) may start avoiding German airlines such as Lufthansa for this reason.
We hope the German government will reconsider this decision that is already affecting thousands of Indian citizens.
Thanks in advance,
Your Name