No, that's a bogus argument. People always try to justify misbehavior by saying that acting appropriately would create precedent, and applying that precedent to a totally different situation would lead bad results. This argument is bogus because you can just...not do the second part.
The actual slippery slope is that making excuses for companies that act inhuman just allows companies to act more and more inhuman.
The actual slippery slope is that making excuses for companies that act inhuman just allows companies to act more and more inhuman.