Scope and direction. The bakery can do everything in its power and still only effect a small subset of people in a certain location. Facebook using everything in its power can arguably effect a significant portion of living humans at the same time.

Second direction of effect. A baker can spray scent to make you think about food, positive or at best neutral effects. Facebook can manipulate what your see to induce rage, fear, hate, xenophobia, anything it wants if it is effective.

Again, I think it really just comes down to scope. Regardless of what precedent there is for corporate interactions with the populace, we are at an unprecedented time with regards to the reach, immediacy, and ubiquity a corporate entity can exert on its users. And when you have a company whose product incentivises immense social pressure on others to join you can end up with huge amounts of influence in a very short time.

Again, looking at it from the precedents of the past you can say there's nothing wrong or different about it but we do not live in the past and these entities are having large and possibly damaging effects on our societies and the precedent with regards to that is to attempt to eliminate it, either through media shaming or governmental regulation.