that is part of the beauty of language. A linguist looks at that word and thinks it is wonderful. The german word for cemetery is "Friedhof" - literally "Place of peace".
Also you are overlooking something very important here. You use it to imply Greek language is weak and primitive, but actually it is part of the development of every known language that has ever existed in mankind.
The word "kite", as you chose as an example. It is from the old english word for "eagle" - "kita". This is how languages develop. Why would someone name something he has seen for the first time, as something brand new, invent a funky new name for something and hope it catches on? That is not how language works.
The word "kite" means "flying tethered paper aircraft" because hundreds of years ago, people saw it and thought "eagle!" and that word caught on after hundreds of uses.
Likewise when Greeks saw a kite they thought "paper eagle!" and that word caught on generation after generation. In trying to show a weakness of Greek language, you have showed how language is a beautiful development taking hundreds of years. The fact that we still have the word "xartaetos" and know it to mean "paper eagle" shows how strong and rich the greek language is - nobody in England is able to understand old english - nobody in England would realise "kite" is a derivation of the old english for "eagle".