On AuthMeReloaded v5.4.0 there was a node called "removePassword" that if you put "false" you could see the passwords on the console. Now I don't see or find that node anymore on any of the newer versions or dev builds.
What happened with that node? Why isn't there anymore? Could it be there again?

Admins should never be able to see the passwords of their users. People tend to use the same passwords on multiple services.

Then, back in the older versions, why was it there that option?

Looks like the feature was introduced in the first commit of this repository (or even before). It's hard to tell, because it's such a long time ago. It could be for compatibility reasons, different level of knowledge or something else.