I became confused by comments to my answer insisting that Technical writing is jargon using incorrect English words.

I also looked through definitions of "prepend" in internet, all with inserted derogatory remarks, even in IT-specialized dictionaries, like 'jargon' and:

• prepend is not an English word. It was created to sound like the opposite of "append," which means to add to the end. The correct English word is "prefix;
• Although it sounds correct, prepend is not an English word. It was created to sound like the opposite of "append," which means to add to the end. The correct English word is "prefix;" for example,

Is Technical Writing jargon or writing-style and the branch of correctly used English?
Would I better avoid to refer to it as English at all while copywriting (or copylefting) in it?

Update:
If I write using the words which are not English WORDS, do I write in English?