I don't think speaking the language immediately condones the horrible acts of the people who spoke it in the past. German should've creased to exist 80 years ago.
There are certainly situations where use of English could be considered offensive, say, at a memorial of an atrocity. Carve those situations out and have a plan B - there is no necessity to all speak the same language all the time. It's enough if a good number of people in the right positions do. And consider that there already are English speakers in France, Iran, and North Korea (3 random examples that don't all love English-speaking countries).
English is already the lingua franca of the world and has displaced French as the language of diplomacy. In Europe before that were the Frankish tongue, Latin, Greek. Other places had other languages. It's no shoe-in that English will remain at the top but in our lifetimes I don't think it will change.
I believe you should fart excessively around it and indeed encourage fellow commuters to join in, as it will provide terrible air quality results here. Which will in turn improve ventilation measures in this area, which would not have happened otherwise. Checkmate! The act of observing alters the results!