Animeboye, by your logic, everyone on That Guy With the Glasses, The Escapist, ScrewAttack and others are committing wrong by not allowing publishers to earn from their reviews.
Also, no, there is no denying this. Doing so would only prove hypocritical because the videos at those sites fall under the same rights as Let's Plays do. Fair Use protection under educational commentary.
Fair Use falls under more than whether or not one makes money off of it. In fact, it's rarely the big deciding factor in fair use cases that are taken to court. To help prove my point, let's look at the rules of Fair Use and how they relate to Let's Plays.
Note: Info in quotes taken from fairusetube.org
FACTOR 1: THE PURPOSE AND CHARACTER OF THE USE
This factor considers whether the use helps fulfill the intention of copyright law to stimulate creativity for the enrichment of the general public. The defendant must show how a use either advances knowledge or the progress of the arts through the addition of something new. The more transformative the use, the more likely it is to be fair, whereas if defendant merely reproduces plaintiff's work without putting it to a transformative use, the less likely this use will be held to be fair. Further, the more commercial defendant's use, the less likely such use will be fair.
Sure, one would argue that just talking over a game while it's being played is hardly considered transformative. However, when it comes to commentary, it's more on what the person is talking about that is important. Are they teaching new players how to get through a level or beat a boss? Are they pointing out flaws in a bad game? Are they making bad jokes or making stupid mistakes that make it more entertaining? As such, it can be educational to the viewer, or even be funny, thus being a parody. Both of which are considered transformative.
On top of this, one can argue that playing a game and watching someone play a game are two different experiences. This small detail would make the simple act of watching someone play rule in favor of being transformative.
Now even though some earn money off of this and it would hurt their case, remember that it is not the big deciding factor.
FACTOR 2: THE NATURE OF THE COPYRIGHTED WORK
The more creative, and less purely factual, the copyrighted work, the stronger its protection. In order to prevent the private ownership of work that rightfully belongs in the public domain, facts and ideas are separate from copyright?only their particular expression or fixation merits such protection. Second, if a copyrighted work is unpublished, it will be harder to establish that defendant's use of it was fair. See Salinger v. Random House, Inc., 650 F. Supp. 413 (S.D.N.Y. 1986), and in New Era Publications Int'l v. Henry Holt & Co., 695 F. Supp. 1493 (S.D.N.Y. 1988). One commentator noted that "the original author's interest in controlling the circumstances of the first public revelation of his work, and his right, if he so chooses, [is to not] publish at all." While some argue that legal protection of unpublished works should come from the law of privacy rather than the law of copyright, Congress amended the Fair Use doctrine to explicitly note, "The fact that a work is unpublished shall not itself bar a finding of fair use if such finding is made upon consideration of all the above factors."
Or to make a long story short, the question here is "Is the copyrighted work published by the company at hand?". Since many Let's Players tend to point out who it is that created the game they are commenting on, this small detail tends to rule in favor of the Let's Player. Without this simple crediting, they'd be in trouble.
FACTOR 3: THE AMOUNT AND SUBSTANTIALITY OF THE PORTION DEFENDANT USED
In general, the less of the copyrighted work that is used, the more likely the use will be considered fair. If, however, the defendant copied nearly all of, or the heart of, the copyrighted work, his or her use is less likely to be considered fair. See Harper & Row, Publishers, Inc. v. Nation Enters., 471 U.S. 539 (1985).
Yes, they play through the whole game, even going as far as 100% completion. They show it all step by step. It is indeed what separates review from commentary, as a review tends to use a limited amount of the material to make their points. A commentary of a game on the other hand, tends to use every bit of the footage.
However, even though this does hurt their case, it's not the big deciding factor in the end.
FACTOR 4: THE EFFECT OF DEFENDANT'S USE ON THE POTENTIAL MARKET OF THE COPYRIGHTED WORK
This factor is generally held to be the most important factor. See Harper & Row, Publishers, Inc. v. Nation Enters., 471 U.S. 539 (1985). This factor considers the effect that the defendant's use has on the copyright owner's ability to exploit his or her original work. The court will consider whether the use is a direct market substitute for the original work. The court may also consider whether harm to a potential market exists. The burden of proof here rests on the defendant for commercial uses, but on the copyright owner for noncommercial uses. See Sony Corp. v. Universal City Studios, 464 U.S. 417, 451 (1984). It is important to note that courts recognize that some market harm may come from fair uses such as parodies or negative reviews, but that such market harm does not militate against a finding of fair use.
THIS is the big one. Does it help or hinder in getting the word out about someone's work? Sure, negative commentary happens all the time, but that doesn't seem to stop an audience from learning more about it and giving advice to the company at hand on how to do better with their next project.
Positive or negative, commentary gives a product more attention. Let's Plays have a huge advantage on this one.
So, it stands to say that there is a good chance that in court, Let's Plays would fall under Fair Use, thus being protected from problems like these.
There is no two ways about it. Whether or not a Let's Play makes money, it is protected under Fair Use. As such, by effectively rerouting where the funds of the Let's Player go, Nintendo is the one committing theft in this case. Not the other way around.
Plus, it just creates bad PR for Nintendo to do this. Fans will boycott, thus making Nintendo realize that they made a bad move on their part.
Just watch. This won't last.