Nothing, but me and my devices, should ever have a reason to access my email. If someone or something is trying to access my email, even with explicit permission, there's no way they can be up to anything good.
The activities that originate from LinkedIn touching your email account is definitely sketchy at best, and definitely spam. There doesn't seem to be a good way to stop unwanted emails going to a single address.
Hell, I've found that even getting them to stop sending you emails regarding your account / groups you joined doesn't always work. Speaking to their support department ends in a response with something like "our engineers are aware" with no change in behavior.
Half of me wants to just get rid of LinkedIn, the other half of me likes seeing old acquaintances getting promotions/moving on to greener pastures.
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Dear LinkedIn,
Please stop being scummy...we'd all appreciate it.
Cheers!
-Everyone from the Internet