The vegetarian analogy is a great one actually.
To the 'don't breastfeed in public, you might offend someone' brigade:
If you were in a restaurant enjoying a delicious steak, and someone was staring at you and muttering things about meat being 'disgusting' or something, would you think 'oh my, how inconsiderate of me, of course some people are going to be offended by this, I shall finish my meal with a napkin on my head or better still I shall go and finish it in the toilet'.
Or would you think 'gosh that person is rude, if they don't like it they don't have to look' and continue enjoying your steak?