I don’t understand why LinkedIn is and need to be so heavy and slow at all. In a way, similar to Facebook I guess?

Even though they provide several services - social network, jobs (for hiring managers and jobseekers), learning etc., none of them really have any tight integration with each other and can easily exist as separate services.

The website and apps are clunky and slow to load and has tons of dark patterns (contacts upload, profile visit tracking, everything over-shared by default, email blast when you sign-up etc.). I have heard LinkedIn hires lot of bright people and pays them quite well - but why their product still sucks?