Facebook makes algorithm changes to reduce unpaid reach and squeeze more money out of business entities on the platform regularly, almost as soon as the complaints from the last round of changed have died down; it may be a contributor to background frustration especially by small businesses (for big businesses with established brands, its a barrier to their competition) but it'd probably not as big of a contribution to the present controversy as direct political features of that controversy, where the left is upset at the impact and therefore everyone involved, the right wants the political focus on Facebook rather than the other parties, and privacy advocates are angry at everyone involved, but particularly Facebook as the direct custodian of the data, about the mechanisms which allowed it to happen, which leaves everyone mad at Facebook for one reason or another.