It's as though you're being bullied by two people, and when you try to deal with one of them, you're accused of being unfair because you can't deal with both!
It sounds very much as though it was the bullies who decided what was "fair" in this instance.
I didn't say it was right, I said it was different and that your reframing wasn't appropriate.
What changes? For a start, the more people that are involved, the less each knows of the situation. A single individual being bullied is aware of each incidence and what it going on at all times. A group doesn't - witness mob justice as a clear counterpoint. A group is highly susceptible to hearsay and misdirection.
As for why it's unfair - if we expect the judicial system to be fair when it acts on our collective behalves, it is dissonant to not expect other group action to also be fair in how it's meted out.
I don't see why a group being "susceptible to hearsay and misdirection" is a good reason for their ire to be directed at more companies rather than just one.
I also don't see any reason why a group fighting against the injustices they can tackle, obliges them to take on the ones they can't.
EDIT: To take your example of the justice system - if I steal from someone, it would not be a valid defence to point out that other people had not been successfully convicted of stealing, therefore I should not be prosecuted.
It sounds very much as though it was the bullies who decided what was "fair" in this instance.