It's not necessarily a bad look for the team even if it is true. All coaches want to work with the GM they select and Glenn has long planned to be a package deal with Newmark. There is no indication that even if it happened that it was because Glenn thinks Loomis is incompetent. And there are credible sources, specifically Underhill, who says that despite what our fanbase thinks, Loomis is well thought of in NFL circles.
And the only reason we are discussing it is because we want to believe that it's true and we want to believe that people in the NFL think Loomis is incompetent because it would confirm what we think is true.
And it's possible that what really happened here is that someone who knows Glenn said that he took the Jets job because they agreed to hire Newmark as the GM and he didn't really consider the Saints because they already had a GM. And that then turned into he demanded that they replace Loomis as GM by the process of the telephone game.
I don't find it hard to believe at all that he chose the Jets over the Saints because he could get the GM he wanted. But, I do find it hard to believe that he went over Loomis' head to demand that his guy be named GM or he would not take the job. Especially when there are very plausible reasons why Glenn would take the Jets job over this one including living in the NY area where his wife like living, they have a better and younger roster (especially on defense), he was drafted and played for the Jets for 7 years, and he could pick his own GM. Frankly, I always thought the connections to the Saints were somewhat wishful thinking when he barely played here and only coached here for 4 years and that was under Payton who is gone. All of which makes it less plausible that he really wanted the Saints job so much that he was willing to go over Loomis' head and demand that he be allowed to select his own GM.