It's not saying you should do it discreetly Tequila (which would not be acceptable either).
In order to breastfeed my child my breast needs to be accessible to that child. If I put it away it is not accessible. It is quite clear they are saying
'Some people think women should not breastfeed in public. We stand with those people and support their opinion'.
That is actually what the ad campaign is saying.
Unfortunately for them, it is illegal and discriminatory to tell women they may not breastfeed in public. So they really need to think about why they are promoting the fact that they support an illegal act.