I made this LinkedIn Filter that hides posts by content type and promotion. I needed this for my other project. You can also filter political content by adding keywords.
Happy productivity hack!
Extension: https://chrome.google.com/webstore/detail/linkedin-filter/fbmgelidpfgehgngajehiidbohdafagc
Github open source: https://github.com/massanishi/linkdein-filter
PS: I shared it on Reddit. And it was well received, therefore resharing on IH:)