There are only a few possible explanations really.
The WT writers and the people who sign off on them are very ignorant of what it means to present an article that is journalistically sound.
The WT writers know full well what they are writing is questionable but are under instruction to present the info that way.
I find it very difficult to believe that the WT writers are that stupid or ignorant, but I do believe the WT heirarchy is that deceptive and the writing department does what it is told. IMO.