You can read x articles a day; your system ingests y articles a day.
x=y is perfect but requires close-to-perfect balance (if x=0.9y to 1.1y maybe you can adjust your reading habit to your your feed)
if x>y then your system isn't showing you enough, if y<x you are going to miss things you subscribe to based on some arbitrary or random characteristic.
With an algorithmic feed of some kind you choose to read x items a day, your system shows you the best x items a day out of y based on some set of criteria and constraints.
These things are common sense but seemingly nonsensical to a lot of people. For instance our impoverished rights-based discourse (see [1]) about "free speech" presupposes that 100% of people can read 100% of what everybody else posts, realistically platforms can only show people some fraction of what gets posted so one thing is going to get more visibility and other things get less and that's a choice -- it could be random but it's still a choice. (As Rush would put it, "if you choose not to decide, you still have made a choice")
I think the discussion is so impoverished that we never hear that an algorithm could choose to do anything other than maximize profits for a platform, when in fact that is just one thing an algorithm could do out of countless options.
[1] https://www.amazon.com/Rights-Talk-Impoverishment-Political-...