I find the over 80s generally very supportive of bf, probably because lots of them did it themselves. I used to get a lot of comments like 'well done!' and 'beautiful baby' and 'good for you!' which was incredibly sweet.
Babyboomers seem to vary and are not sure what the reaction ought to be, unless they have bf themselves, which would have been rare, but IME they kind of let you get on with it as long as you don't take your entire top off and preen about it.
Teenagers and oafish blokes (and their wives) are the most thrown by bf, probably because they have never seen it happen before.
I think what we need is a new framework for the etiquette of feeding, and for this to be publicised properly. For example, offering a glass of water, offering a seat, offering a choice of a private place to feed (perhaps for the early days) or a public place (when it's more established or when someone is out with her family), that kind of thing, while emphasising that mothers are just getting on with something they have been doing since the beginning of time immemorial.
If there was ever a need for a public information film on TV, right in the middle of prime time, this was it. The MN campaign is a start, but not really enough as it's not about good places to feed, it's about publicising the fact that it's completely normal and acceptable.