"People are missing the point if they think Kelly is mad at Michael for taking the job," a source tells PEOPLE of the news that Strahan, 44, will be leaving ABC's Live! to join the network's Good Morning America as a full time co-anchor in September. "She totally understands why he'd take the job ... it's a great job!"
"She's not of the opinion that signing up with Live! has to be some sort of lifelong commitment," continues the source. "But there is a way to go about things, with courtesy and respect and decency, and none of those things were done here."
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According to the source, Ripa, 45, only found out about his departure when the news broke Tuesday.
"She was told at the same time as the rest of the world was learning via press release, and she was told in a room full of suits, and Strahan just sat there, mostly mute," says the source.
"How do you not have the [courage] to at least go and say: 'Listen, I want to talk to you about something,' – ideally months ago when this all started, so she'd have time to adjust to the idea – but at the very least, how do you not do it before 10:30 a.m. yesterday?" the source went on. "That is just cowardice."
"He could have said something, and he should have said something," adds the source. "This is not about him taking a new job. It's about him being duplicitous ... about not including her."
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"She is showing them as much respect as they showed her," says the source. "She knows that by not showing up she is showing the world that she is hurt and upset, and she is fine with that – she doesn't care if people know that."
"If [anyone] is trying to spin this as her being some sort of crazy person who just flew off the handle and can't bear the thought of him having a bigger and better job, that is such a load of crap," the source went on. "And that's them trying to divert attention away from the real issue, which they can't dispute: She should have been told sooner and more respectfully, and she flat-out wasn't."
"She's been the bigger person a million times, when Regis [Philbin] left, when the co-host auditions were dragged out forever ..."
Of Philbin, Ripa's former Live! co-host who left the show in 2011, the source says he "basically did the same thing, only on live television."
"[Philbin] gave her zero clue that it was coming, and in no way gave her a heads up," says the source. "But that just proves that it's not about leaving to take a new job to her – it's about leaving in a way that shows her no respect and no consideration."
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The source also slammed any reports that Ripa might not be easy to work with: "She is absolutely not difficult, and no one has ever said that. She does not have that reputation."
A source expert in crisis management, meanwhile, tells PEOPLE that if Ripa did indeed find out only once the press release was circulating, "then she has every right to be upset."
"That is some serious mishandling on the part of the network. That is not how you do it," says the expert. "There is a way to have someone leave that won't hurt too many feelings or step on too many toes, and one of the key elements is to talk to the people you're leaving behind as early as possible ... so that they can prepare accordingly and feel like their position of authority is being respected."
The expert found it "very surprising" that Strahan wouldn't address the news with Ripa beforehand, and says the same for network executives.
"Why not make sure you've got her on side and ready to support the news well in advance? That makes no sense to me," says the source. "There's a way to handle these matters so that it never escalates to this point."
Live! With Kelly and Michael airs weekdays (check local listings).