I figured this had to be the case for some folks, otherwise it would have been fixed long ago. I'd be curious to know what your setup is. I'm running Mac OS Sierra on a 2013 MBA, connected via Comcast in the heart of Silicon Valley. My computer isn't a speed demon, but it's also not a slug. LinkedIn is by far the slowest website I visit with any regularity, and I have tried script blockers and such to no avail.
From here in Australia, on an i7 with 16Gb RAM, using the gigabit link in my office, I see multiple second loading screens with the circular "loading" animation in both Chrome and Edge. It's by far the slowest site I've looked at on a regular basis.
You see a circular loading animation? For me, it's a horizontal bar with a blue bit that dances left-to-right.
Maybe it's slow trying to pull the A/B testing configuration.
I see the horizontal loading, and it is also very slow (30 seconds + in some cases)
Across the board for me, ranging from old Air running Sierra to '15 MBP. Air at home is on FiOS, MBP at work has decent network. US East Coast.
browser? any blockers/extensions?
Across browsers, Safari is stock, Chrome has maybe a million extensions but nothing that would affect LI, FF is mostly bare but a very old version (42?) due to a work requirement.