Do you honestly believe that most users who will install this will fully understand the ramifications of that choice? if yes, why do you think that, in spite of all the evidence that most users are clueless about security? If no, then in what sense are they really giving consent, if that consent is not informed?
I don't get why this is any different to anything else. What's to stop Microsoft backdooring the next Outlook, MSWord or Windows itself? Why is there so much ZOMG-FUD over this from LinkedIn than there is over anything else?
"Most users" blindly type the same password into Facebook that they do for Twitter, LinkedIn, Gmail, OK Cupid, eBay and PayPal. Any of those services can (and do) get hacked and the password opens all the other services. Should we shut them down too?
By this rationale, almost nobody could ever install any software at all. In practice, LinkedIn's software may be a blunt instrument that I would not want to use, but the vast majority of software really is run on faith based on the provider's reputation. (And yes, it does sometimes bite people, even with things that are not LinkedIn Intro.)
The idea is to be consistent, not please the majority.
I can't say if people's understanding of how junk food is bad for them is greater than their understanding of internet security, but I wouldn't say that they're fundamentally different things.
My point is that "what people understand" is not universal, and is highly subjective. We can't assume that everybody understand why alcohol, smoking, junk food, lack of physical activity, medecine, etc. are potentially "bad" for them. Yet, we don't ban most of these things "in case some people don't understand"?
We teach people about health and nutrition, why shouldn't we do the same about IT (I mean, it's such a huge part of our lives now that we can't ignore it)?
Too many people jump on the "prohibition" train, when it's rarely the best solution. Rather than limit what companies can do (it's rarely objectively bad, they're offering users a feature in exchange for a subjective downside. I would focus on teaching people, not limit what can be done.