Using English as an example and if you remove the Telepathy portion for a second, we kinda do this already. A person within a close enough distance to another to talk can ping that person and begin a conversation. A persons mind still exists as conceptual, the English 'translation' that goes through our head is just that...a translation of the conceptual (I'm of the opinion many people mis-identify this translation layer in their head as themselves and fail to admit the conceptual). Human interaction becomes conceptual translated to english, communicated to another, and translated back to conceptual for that person to understand. A "failure to communicate" usually lies with one of the communicators failing at that translation level and not the communication of words.
As such, English is an exceedingly exacting language where one word or phrase can really only be translated to conceptual in one manner. It's also the layer in which we add the 'political' or 'politeness' touch, choosing what information to convey and how to convey it. Without this translation layer, concept to concept communication would be exceedingly blunt, honest, and potentially destructive.
Me conceptually - Oh great, this person is an absolute waste of humanity and should be torn limb from limb for the way they treat other humans.
Me post translation layer - 'Hi, how are you?'
In short - your very good reason is concept to concept can really only happen between two very familiar and very trusted peoples, or they are going to share concepts they a) dont want to and b) in a manner they don't want to.
