Exactly, these profiles are not public anymore (in the common sense meaning of "public profile"). BTW LinkedIn and others are doing the same, and what anyone is going to do about it?
Stop using their user-hostile service? They need my eyeballs in order to sell me to advertisers. If they are creating features that turn users away, their bottom line may be impacted enough that they reevaluate their user-hostile business practices.
Open an incognito window and try going to a linkedin profile. Then try it with google translate: https://translate.google.com/translate?hl=&sl=af&tl=en&u=htt...
Odds are good you can still view the profile through translate because linkedin thinks you are google.
LinkedIn, Pinterest and others want to be indexed by google, but don't want the content that's indexed to be public. Google is ruining their own service by allowing this to continue.
Then, they changed it to third-and second-degree connections only, so you had to be signed in. And now, it's completely unusable without an account.