You wrote "to explicitly hurt your company". I'm not sure the word explicitly actually changes the meaning here. I could campaign to introduce a carbon tax. I'm not doing it to explicitly hurt my oil company employer. Even if I know it probably will at some level.

There's degrees of 'explicitness'. What about campaigning against fossil fuels if you work for an oil company? What about a car company? Theres a line, and I'm willing to bet it will differ from employee to employer.