The Let Girls Be Girls campaign will have an impact on both boys and girls.
I imagined that the premise of it was to stop the early sexualisation of young girls so that girls didn't see themselves as sexual objects, there to fit into a stereotype for male consumption, and boys didn't grow up with unrealistic expectations of how girls should look and act as well (that being the premise - the reality, sadly, is obviously harder to achieve).
A win-win situation, even if it is focused on merchandise for young girls.
I am presuming that MNHQ must have thought that the LGBG link was worth taking seriously because they have been in contact with M&S about it.
I agree that it isn't desirable to kick a company off a campaign but there's not much point in companies signing up if they aren't going to abide by the principles of the campaign. It's a gimmick otherwise, a token gesture that means nothing if a company isn't going to take it seriously. I think M&S should be held to account for it. Other companies will see that it's a pointless campaign then and won't think twice about ignoring the principles that they've signed up to if M&S are let off the hook.
Ideally, I wouldn't see them kicked off the campaign. I would like to see them reaffirm their commitment to it. However, they are remaining silent and have been very dismissive of the hundreds of people who have written in to them.
As others have said, the M&S angle is only one part of the campaign and it was successful with the Ask Pizza chain in Sheffield with only local bad publicity. They were concerned about being linked with 'Hooters' and they hadn't made any commitments to a national campaign or have a 'gold standard' ethical policy, as far as I know.