Phantom Buster has a scraper that scrapes a user’s activities (as in, all their likes, etc).
The main reason, I’d imagine, people prefer to use APIs such as this is because it keeps their account from getting flagged for suspicious activity.

Any plans to add an endpoint on the LinkedIn API for activity scraping?
I know the current endpoints allow you to see the likes and comments on a post, but I’m talking about seeing what a user has liked.

Cheers!