After some consideration, the more I thought about your answers the less satisfying they are.
I already addressed the point that individual investors don't make a measurable difference in share price. Already acknowledged. But exactly the same argument applies to boycotting, voting, or social media campaigns, which you seem to promote as a better alternative.
As for the "it doesnt hurt the company" argument - this had me for a while but then I thought more about it. You obviously can't hurt, or be angry at, a company. Its a non-entity, a legal fiction, a collection of people. Who are the people to blame? Who else can you hope to hold accountable but the owner of the company?
And in a publicly traded company that means the shareholders. They are the appropriate target, not an accident. they own the shit.
Again, nothing we do as traders make a measurable difference. Just like nothing we do as customers or voters or social media people makes a difference. Individually. The effects result from collective action, and adding our miniscule voice to the chorus of people saying "fuck you" to an evil company still matters ethically, in my view, whether it has a measurable effect on the company or not as an individual action. Its about not participating with evil.
The thing is, I think you think this too. Else why avoid tobacco companies?