How do Jehovah’s Witnesses explain the unique wording of Colossians 1:15-17 in the NWT?

Compare the wording of the NWT and the NKJV at Colossians 1:15-17 NKJV says >15 He is the image of the invisible God, the firstborn over all creation. 16 For by Him all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or [a]principalities or [b]powers. All things were created through Him and for Him. 17 And He is before all things, and in Him all things consist. NWT says > 15  He is the image of the invisible God,the firstborn of all creation;16  because by means of him **all other** things were created in the heavens and on the earth, the things visible and the things invisible,whether they are thrones or lordships or governments or authorities. All **other things** have been created through him and for him. 17  Also, he is before **all other** things,and by means of him **all other** things were made to exist, How do Jehovah’s Witnesses explain the usage of the word “other” in these verses? And what support for bringing this word into the text is there among Greek language aficionados?