Today, Barnard Divest, a student organization urging Barnard College (an affiliate of my institution) to divest their endowment from fossil fuels, is meeting with the Barnard administrators and are holding a protest in concert with that meeting. I'm in support of the movement to divest from fossil fuels – a move that Columbia has, thankfully and surprisingly, already agreed to – since diverting investment away from something actively damaging the environment is the Right Thing to Do.
But it brings up a question of how much information the activist side should talk about. Let's say that fossil fuel investments generate a higher ROI than alternative investments and the mean, and that in turn leads to more availability of money for the school. (Unfounded assumption.) If each side were being completely honest, the activist side would bring up this "con" along with their many "pros" to acknowledge that they are aware of this.
In reality, they most likely won't. Bringing it up gives more ideas to the university side to reject the divestment proposal, and that piece of information carries even more weight because "they said so / admitted it themselves".
Is it ethical to omit information that you know is instrumental at arriving at a rational decision to support a cause? If our benchmark is complete honesty, then no. But perhaps a consequentialist would argue that
1) there is an uphill battle that activists have to (unfairly?) fight to state their views, so the burden of proof is more on the activist side;
2) there is a status quo bias on the part of the university to stay the course, leading to more of a burden on the activist side;
3) this inequality of power in this situation may justify a compensatory allowance for activists that would make them reasonably allowed to omit information that tilts the scale toward the already-tilted side (the university).