Mistakes in judgement and boathandling create scenarios where one competitior has the option to protest another competitor on the race course. Just like a lawyer can "object" to another lawyer's actions or tactics in a court of law and asks the judge for a verdict, so do we have the option to use the protest process in sailing when we believe the rules have been violated. You don't hear lawyers calling the other lawyer a cheat when they object in court. They state their case and look to the judge for resolution...
Now this is a purely theoretical post, completely unrelated with whatever happened or did not happen in the US Olympic trials. I wasn't there and do not (can not) have an opinion about it.
Bob's argumet stands true in an ideal, 100% legal, world. But lawyers (and athletes) use several direct legal resources for indirect or secondary purposes.
One example is objecting in court to interrupt the oponent's speech when he is being particularly brilliant, to disrupt his (or the jury's) line of thought, to delay the trials and buy time or to manipulate the judges/jury, and other secondary purposes. The action itself is legal, but the goal is not the one that makes it legal.
In serious chess games the oponents regularly use "psychological war" in the form of protests, requests, delays, etc. to mess with the oponent's concentration.
Obviously sailing is not a mind-only game like chess, but even in sailing, protests might be used for indirect purposes.
Again, I am not saying that this was or wasn't the case, nor that it is fair (or unfair), I just say that it can be done.