Terry will miss Saturday's Champions League final due to suspension.
Lahm said: "I couldn't believe it. I was so surprised, not by the red card but what he did to earn it.
"Would I describe it as irresponsible? Let's just say I would never have done something like that. It simply wouldn't have happened to me. Why? Because as captain, I do everything for my team. That would have harmed them and I would not allow that to happen.
"But that's down to him. Our only focus is on winning and we are not too interested in who might be playing for Chelsea or who might not be.
"I wouldn't say it is an advantage for us that Chelsea will be without their captain. I think the players who are missing from both sides will even themselves out. We are missing players who have been key to us reaching the final, like Holger Badstuber, Luiz Gustavo and David Alaba, so we have suffered as well."