It's just a narrative that took on a life of his own. Tua has a much stronger arm than Chad Pennington did when he played for us. Tua and Burrow were considered to have similar arm strength going into that last year of college, but you don't see people talking about Burrow's lack of arm strength. The difference is that Burrow had some success. And he had deep attempts attempts due to the offense design. Tua hasn't had the same level of success, so people with a simplistic understanding of football or an agenda decide it must be due to arm strength instead of the more obvious poor pass pro, lack of a run game, offense design, etc.