There's one minority still not given proper respect in language: Left handers. The term "sinister" is still used as an epithet for evil, wrong, unpleasant. Likewise, "gauche" is a reference to rude behavior.  People are considered "dextrous" if they have good manual skills.

Why are the negative connotations expressed using references to left handedness, and positive connotations reserved for the right? 

Writers, especially in fantasy, usually right-handed, should stop using these prejudicial terms and find terms that are non-handed specific.

This is a worldwide issue.  Only about 15% of the population are left handed.  Most gadgets default or are exclusively right handed.  

Take scissors--sculpted grip scissors are unusable by a left-handed person.  Neutral grip are usable, but even so-called "left handed" scissors usually are just replacement handles on right handed blades, which cut with a bias that favors the right handed.  Hacksaws, metal shears, vernier calipers, can openers, are all right handed by default. Most modern locking pocket knives have a right-handed lock and pocket clip.  Historically, all swords with a swept hilt, shell guard or wire hilt are right handed and just don't work for someone using their left.  Most sheaths are right handed.  If you shoot rifle, forget shooting a bolt action--they're almost all right handed.  Anything left handed costs a premium, even in the modern day when it's easy to reverse the action of a digital milling machine.  Shooting jackets--right handed.  Telescopic and optical sight adjustments, as well as most adjustable iron sights--right handed.

Musical instruments--anything stringed is right handed, and to reconfigure the bridge as well as the strings, and perhaps even the pickups, not to mention any onboard controls, takes effort and money unless the company makes a left-handed variant (most classical instruments DO NOT).

Most computer mice are right handed--trackballs tend to be right handed only.  Until recently, even most jacks were configured to place the mouse on the right.  Putting it on the left took workarounds.  The numerical keypad is on the right.

 I'm sure most people have never thought of this.  They have right-handed privilege, in a world that caters to them.

I'm sure some will dismiss this as a non-issue.  I challenge them to go into a store and ask for every household good in a left-handed model.  If the store has any, they will have a token one or two of each, not the dozens or hundreds of right handed options.  Buy them.  Go home and use them in your right hand so you're using them backward. That's what it's like for left handed people every day of our lives.

Politically, I've seen conservatives refer to the political right being "correct" and the political left being "wrong."

Then crack open a book and find the bad guy is "sinister" and the clueless guy is "gauche."  Gee, thanks for that.

"Right" is an acknowledgment of correctness.  One gets "left behind."

I expect there are a number of fantasy writers who are major offenders on this.  But if they're taking steps with racially, culturally, gender and religiously sensitive terms, it would be fair to not use terms derogatory to the left handed minority as well.

I don't suffer as much as others--I'm largely ambidextrous.  But let's look at that word.  "Ambi" = "both."  "Dexter" = "Right."  The word defaults that someone with flexible manipulative skills is "both right," not "both left."  Since I DO have a slight favor to the left, I am correctly ambisinistrous.

It's not been long since it was a social crime to be left handed, with most cultures forcing right handedness on children.  We're past that in most of the world, but a number of cultures and subcultures do still enforce dexter dominance.

Let's start by not using "sinister" and "gauche" in our writing.  These words are archaic, insensitive and prejudicial.  If we can take this step, we can then work on neutralizing other orientation biased words.
ETA:  I'm informed gaming consoles are usually right handed, and keyboard game controls favor the right. And let's not forget that it's considered rude to shake hands with the left (the Boy Scouts have actually addressed this, with a left-handed handshake).

Look around, and you'll see the bias is everywhere.