Ceto
That's not a biased campaign, it's just a campaign. By its nature, every campaign asks people to do something that supports the campaigners' viewpoint.
Exactly. It's biased towards the campaign's viewpoint. They want brands to pull advertising from those companies they think are full of hate. It's not a neutral research group. It's a campaign with a viewpoint. It's biased.
But frequently they're doing little more than responding to a general perception of what their customers want, and that may well in part result from Facebook, Twitter and direct communications.
Paperchase can't even have formed a general perception of what their customers want since a) they didn't verify that any of the SFH campaigners were customers anyway and b) they only looked at the complaints. Nobody else even knew there was a campaign against them which customers could counter. That's not just no market research, that's not even getting a general perception of its customers.
that is the relevance of the my comment that this is a marketing campaign, as opposed to, say, an election or an opinion poll.
So what? We haven't been discussing election or opinion polls. 
No doubt they can now start their own campaign to get the decision reversed.
Yes they could. But that's not what we're discussing. 
Strangely, they don't seem to have rushed to do so, so maybe Paperchase have got it right when assessing customer reaction.
Maybe some people are. Maybe some people can't be bothered. Maybe some people will stop shopping at Paperchase. Who knows?
if they loved the tie-up with the Mail so much, they could have flocked to Paperchase to buy things to show their approval.
Who said they loved the tie-up? 
if Paperchase thought the connection with the Mail was boosting its customer base I suspect they'd have ignored HNH
And.. so what? 