"Open source" does not mean that you can reuse the deck for commercial purposes. A lack of an explicit license means that you cannot assume you have any specific permission to use the content, especially for commercial purposes.
Just because they are published does not mean that you can host them, potentially modify them, and sell access. That's like the same thing as scraping Medium.com and re-selling access to all of their articles on your own site.
Just because they are published does not mean that you can host them, potentially modify them, and sell access. That's like the same thing as scraping Medium.com and re-selling access to all of their articles on your own site.