It's just your perspective on language. Just imagine that you grew up speaking Lojban and you're looking at English. What's the purpose of "to" when it's intrinsic to the word itself anyway? I imagine a Lojban native would have trouble understanding "to" or "from". You're still thinking terms of your native language, so to you "implies 'to' already" is bad thinking. It's more like a function and less like a 'shortcut' to an English phrase.
So, in short, stop trying to relate it to English.
It's not a shortcut and it doesn't imply anything.
It's a language on its own. <3
I think it's natural (in fact I would argue necessary) to relate to the structures (cognitive and linguistic) which the second language learner already understands. I'm not trying to change Lojban into an English model of language. I'm simply saying that it may be less ambiguous to explicity state which role you are communicating rather than assuming that the listener knows the place structure of the brivla.