Oddly, I think it's more controversial now than it used to be. That's odd because we are supposed to have fewer taboos nowadays rather than more.
I never found that my breast-feeding outside the home caused any controversy. Nobody said anything negative or even looked anything negative, ever. Sometimes someone would smile and once someone commented approvingly on my happy baby when the feed was over. That was on a train.
I'm amazed at the fuss that sometimes happens nowadays and the outrage some people express, but for every story of fuss there will be hundreds of babies being breastfed 'outside the home' with no fuss or bother from anyone. I think that's worth remembering.