That entire argument works as long as you redefine the dictionary definition of normal. You don't just get to take your pink glitter pen and start editing the dictionary to fit the nonsense that comes out of your mouth. Not to mention that cis is clearly most often used as derogatory term.

Redefining normal to mean acceptable, not perverse, insert positive thing here, etc and not what most people do doesn't do anyone any good. By the dictionary, most people are not trans and therefore trans people are not normal. This is the correct use of words and shouldn't be offensive, but it is. And will be to the point you'll willfully disregard anything and everything I could possibly say to be offended despite none being intended. As is the subject of this post.

Not to mention what you said wasn't why straight came about at all:

http://www.pbs.org/wgbh/pages/frontline/shows/assault/context/katzhistory.html

Why is it that the trans community is filled with people who will claim to speak for everyone, claim to know what's best, and why are those people the most likely to be thought police?