Bottle feeding guilt is real and I hate it

We're using formula with our 3-month-old twins because my wife couldn't produce enough and honestly the stress was destroying her mental health. I know fed is best and all that, but I still get weird comments from some of our friends and it bothers me more than it should. My MIL keeps suggesting my wife 'try harder.' Anyway I think our babies are thriving so why do I still feel defensive about this? Just needed to vent.