Why is this legal on Patreon but not on YouTube?

It’s not a criminal thing, just copyright law. There are rules for fair use in the context of commentary and criticism of the original work, but each one would need to be evaluated on a case-by-case basis. YouTube has implemented it’s strike policy to try to prevent it’s platform from being used to violate copyright (thereby exposing itself to lawsuits from copyright holders). Because Patreon content is blocked by a paywall, it’s harder for copyright holders to scan for content they believe violates their rights. IANAL so I’m sure my answer is incomplete, and probably not 100% accurate.

Youtube has their bots that nuke videos automatically, whereas Patreon embedded videos might use other hosting sites, that are more “lax” with their banhammers.

What do you mean by a reaction?

You mean a review?

I’m confused, because I regularly watch reviews of movies on YouTube. They seem to be very popular.

I’m not sure what I’m missing.

Are you talking about posting someone else’s entire movie or album, with your comments dubbed over it?

@gorillapaws is on target in terms of the policy differences between Youtube and Patreon. They’re both privately owned for-profit media businesses, and within constitutional & legal limits are free to set whatever terms they choose for creating and using content on their platforms. What it comes down to is varying interpretation of US Copyright doctrine on “fair use”, which actually allows fairly broad privilege :

”Fair use is a legal doctrine that promotes freedom of expression by permitting the unlicensed use of copyright-protected works in certain circumstances. Section 107 of the Copyright Act provides the statutory framework for determining whether something is a fair use and identifies certain types of uses—such as criticism, comment, news reporting, teaching, scholarship, and research—as examples of activities that may qualify as fair use.

“There are no legal rules permitting the use of a specific number of words, a certain number of musical notes, or percentage of a work. Whether a particular use qualifies as fair use depends on all the circumstances.”

- US Copyright Office / Fair Use Index:
https://www.copyright.gov/help/faq/faq-fairuse.html

I was referring to YouTubers who do a running commentary of a movie or music album. To avoid a copyright strike, you have to edit the video to not show the entire film. But you’re able to show the entire film on Patreon.

@rockfan “To avoid a copyright strike, you have to edit the video to not show the entire film.”

That’s not completely accurate. I could upload a video of myself doing a running commentary over an entire film on YouTube. The copyright holder might issue a strike and YouTube could flag it or whatever they do. I could then hire a lawyer and sue the claimant asserting my content is fair use. If I win the lawsuit against the copyright holder, demonstrating that my content is sufficiently transformative and whatever other conditions are necessary in court, then YouTube will remove the strike and restore the content. This isn’t generally done because it’s so expensive and I think if you lose the suit you’re on the hook for some massive damages plus legal fees. IANAL.

It is not legal on Patreon, they are skirting the law with a pay wall. They don’t use bots like YouTube to clear copyright infringement.

YouTube is a monopoly (competition doesn’t have access to comparable content library) while Patreon isn’t. Therefore YouTube lost track of the customer as the #1 most important thing a company has because monopolies don’t care about you or what you want. Other priorities are more important to YouTube but Patreon isn’t so bad at this point.

Patreon has far less users than Youtube, so they have less threat of liability from copyright holders. Furthermore, Youtube has more copyright-detection algorithms than Patreon, simply because Youtube is more advanced and has more money than Patreon.
You’ll notice a lot of copyrighted material on Archive.org, for example. It’s not legal. But copyright holders don’t see Archive.org as a threat, simply because they have far less users. Sites similar to Youtube, such as Odysee, are able to host more copyrighted videos because Odysee isn’t seen as a threat by copyright holders due to having far less users.