I agree with the overall sentiment of this post (cutting players who are carrying dead weight) but your context and framing is a bit off.
Re: McDowell, he was a second rounder, not a first rounder, and I’d hardly call him a reach (outside of hindsight). He was a physical freak and universally considered a first round talent.
Re: Chaz Green, he’s an interesting case to me in that we may have done more harm to him than good by switching his position from T to G, then putting him back at T. He looked solid in limited action in 2016 before his notorious showing last year.
All of that notwithstanding, I do agree that we need to be a little more aggressive on roster decisions.