I have some sympathy with your view but doesn't that end up marginalising people who stand up for things?
Bullshit. The entire history of the labor movement chooses to disagree. Employees have far more influence than customers in influencing company direction.
It is the moral and ethical responsibility of individuals enjoying cushy paychecks to ensure they don't come from creating harm to others.
What you're saying is that corporations should be able to bribe employees into accepting an unlimited amount of harm, when in many cases replacing employment and continuing one's own livelihood would be threatened by doing so.
That's horse shit and somewhere deep down, you fucking know it.