Christ is The God Man -Jehovah in the flesh, page-76

Well, tonio JWs essentially believed what Watchtower formulates so we shouldn't blame MrG.
Their NWT is an attempt, it seems, to reflect their beliefs.
Any attempt to alter a document or set of documents like the bible to reflect a set of beliefs that are not all incorporated in the original is a slow, laborious process.
It seems that Watchtower has not got round to altering 1 John 5:20 yet.