According to the documentation, using "SetSessionEnabled()" with the "Enabled" argument set to false will disable a command, whereas "GetSessionEnabled()" will return true if a command is disabled.
While this is the case with "GetSessionEnabledByCategory()", "GetSessionEnabled()" will return true if a command is enabled, returning the same value passed to "SetSessionEnabled()".
While the current behavior of "SetSessionEnabled()" doesn't match the documentation, personally I feel it's more logical, both because it matches "SetSessionEnabled()", and because the name of the method leads you to think you're checking whether a command is enabled; Having true mean "yes, it's enabled", and false mean "no, it's not enabled" is more intuitive to me than "yes, it's not enabled", and "no, it is enabled".
In fact, initially I was assuming "GetSessionEnabledByCategory()" was the erroneously inverted method, until I double-checked the documentation.
EDIT: Resolved in v1.7.3.10; Get and Set now use the same value(true for enabled, false for disabled).