Okrand did not say "MUST always" take an object, he just says that it "would be weird not to" have one.

Think of the English verb "love". You can say "I love you" and "I love cookies" - but just saying "I love." seems weird, doesn't it? And I'm sure there are words much weirder to say without object.

But weird doesn't mean rare. There are perfectly understandable reasons why one might use the verb love without an object: "Oh, please. Don't let them take me. I can't even touch them! Janice, they can't feel. Not like you! They don't love!"

I don't think Okrand is saying rang is only objectless in rare cases. Weird means that while there's no actual rule requiring any verb take an object, rang really needs an object to make sense. Same with ngI', which someone else quoted.

The difference, though, with rang versus ngI' is that I can easily understand what rang without an object would mean: be responsible for things in general; while ngI' without an object truly is weird: have a weight of a general measurement? But Okrand says rang without an object is weird, so we must accept that Klingons find it so.

So I think it IS ungrammatical to use rang without an object, but it is ungrammatical SEMANTICALLY, not syntactically. There is no syntactic rule that says a verb must have an object, but the particular meaning of rang forces it to have an object. To leave off an object is not syntactically incorrect, but it is still wrong.

-- 
SuStel
http://trimboli.name