Say What You Mean & Mean What You Say

This is just a rant, inspired by some social situations I'm experiencing and I am struggling to understand.  Being on the autism spectrum makes it difficult for me to decode social interactions.  I'm not saying this is true for all autistic people -- I know a handful of very social autistics -- but for me, it is difficult to make and maintain friendships and often those difficulties stem from challenges relating to communication.
Oftentimes, I can see that there is a deficiency in my knowledge or my understanding, but it takes me a while to find out why.  So, upon reflecting, I think it all has to do with my own philosophy of "say what you mean and mean what you say."  Specifically, because not all people say what they mean and mean what they say.  So, voila, my thoughts:

I don't like liars.
I don't understand lying.
I don't know why people would say something that they don't mean.  The whole purpose of language is to convey meaning and truth, so why would anybody distort that?  Stating untrue things literally defeats the purpose of language.  Lying is not communication because it does not convey information clearly.
I have told many a "white lie" in my time.  But when I say something, I mean it.  When I say what I want, I do, indeed, want that.  When I say what I need, I do, indeed, need that.  I try my best to communicate clearly.  And I hope that others will communicate clearly with me.
It is frustrating when people lie to me.  It is frustrating when people say things that they know to be untrue.  It is frustrating when people say things, then I behave in a way congruent with what they have said, but I later find out that they actually would want something else.
I don't like it when people leave me "out of the loop."
I don't like it when I am the last one to know things.
I don't like secrets.  I don't understand why we need them.

What You See Is What You Get

I am talking about the common expressive phrase "what you see is what you get," which has a meaning similar to "say what you mean and mean what you say."
I say what I mean and I mean what I say.
Some people call it "brutal honesty."  Some people just call it "honesty."  Sometimes, it can be considered "rude," although I rarely can delineate these times from the rest.
I have been known to tell people that I do not like them.  I have been known to take thoughts that should remain "internal" and vocalize them externally.  I don't do this to frustrate or to anger; I do this because this is how I understand the world.
Language is used for communication and I have great respect for language, thus great respect for communication.  So the idea of communicating in an unclear way is completely foreign to me.  I am twenty years old and I simply do not understand the reason some people feel the need to lie or to mold their truths in a new way.
Recently, I realized that not all people communicate the way I do.  I do not mean that not all people communicate verbally -- of course I know this, I know many non-verbal people -- but rather that not all verbal people use language solely to tell truths.  A woman in class complains about another student's obnoxious personality, but as soon as the student in question arrives, the woman is as kind to her as she would be to a sibling or a best friend.  Why?  Has her plane of existence shifted and she is now in a dimension where she enjoys the company of this person?
For a lot of people, this is easy to understand.  I explained my situation to my mother who told me that this is just how some people are.  But for me, this is a complicated concept to fully comprehend.
Is this the fault of autism?
I don't know.
I just know it confuses me.