Because this is an opt-in feature, the GDPR has tried to limit pre-ticked boxes for opt-in consent. In this case you would have to tick the box to say you don't want to be part of it, but then you'd have to go into the managed settings to reconfirm that. Is that not a bit much? If somebody consents or doesn't consent, why do they have to go through the second step to confirm that? Why is the first step not sufficient? A lot of people may not know they have to take the second step to confirm what they wanted to do in the first step.
On April 19th, 2018. See this statement in context.