if that's what I want give me the option. or let me choose to see everything from my friends and the most popular from my feeds. and maybe even with options to see all the stuff from a feed together and to expand out to everything for that day/feed. with a way to mark things that I've read that I don't want to see in my feed anymore (or reduce it to just a headline to make it easier to scroll past quickly.
lots of ways they could do it
Why let you choose if their data shows it'll just make you less likely to use Facebook? Why would they make a move that they know would hurt them?
Look at Apple. They're another great example of the fact that it's not beneficial to give people a choice in every situation.