A company that does a good deed will draw attention and support away from other companies. If the good deed was done for ethical reasons, then that attention and support will feed further good deeds in the future. If it was done for manipulative reasons, then it dilutes the money going to the more ethical companies. The manipulative company is less likely to do good deeds in the future. It's more likely to ignore opportunities, or to do easier and less meaningful good deeds.

In other words, it's not a one-off. There is the same positive effect in the short term, but the long term differs.

All of that logic could easily apply to this scenario.

For a simpler scenario, if a company does a good deed to apologize for a bad deed, and the good deed is smaller but gets them off the hook, then that's a very clear net negative.