I have no dog in this fight, but I was at LinkedIn at the time, on teams that worked closely to this. I can assure you that these changes were not made to force log in. It was a recommendation from the security team.
I know it's Hacker News and it's easy to criticize LinkedIn for shady growth practices and get praise for it. They often deserve it, but assigning malicious/growth intent for every change they make is misguided.
I'm not an expert, but i understand that redirecting to the app store is an explicit decision on part of the developer (and in Fact it only happens randomly), and a very anti-user one.
The security excuse is used as a way to increase conversion.
I know it's Hacker News and it's easy to criticize LinkedIn for shady growth practices and get praise for it. They often deserve it, but assigning malicious/growth intent for every change they make is misguided.