Well let’s just mini analyze the current case for the recommended password managers that are not open source and they are on the list.
1Password
The product even as an online closed source password manager has endured in time. But it is and will probably always be an online closed source password manager. Only by that definition nobody will be surprised if something like what happened to LastPass happen also to 1Password.
There are plenty online open source alternatives with good reputation already like Proton Pass and Bitwarden that keep listing 1Password makes no longer sense.
Strongbox
That’s an one-man freemium project which source isn’t available to build the app, even some parts are posted on their GitHub page.
Only because of that, should mark the project shady.
The only reason is it listed it is because of the iOS + macOS support, compared to the real open source iOS password manager KeePassium which is also lately got audited by Cure53 that doesn’t have macOS support.
Though, they both are using the KeePass protocol that it is cross-platform so it makes no sense to list an inferior password manager. (KeePassium with KeePassXC for iOS-macOS combo is more than enough for example)
Lastly about the talks to divert the topic of requiring also open source for hardware keys and what is the real meaning of open source is just whatever.
Hardware keys are already in another section of the guide, they can have their own criteria as long as there are not enough options at the moment.
And trying to solve in this thread the meaning of open source, just to keep a paid online closed source password manager and a shady freemium password manager on the recommendation list is just absurd.