Earlier quoted context omitted.
I've stated before that I don't want to work at a job without intending to actually leave the job or having a last date. In those cases I was venting and was burnt out. I've even admitted this to managers I could trust to talk about how to unburn me instead of declaring I've 'resigned', because I bring a lot of value to teams I'm on.
I am quite sure you didn't send email to fellow employees asking them to immediately stop work on the projects they were working on. I am assuming that was the red line, I am not a manager but it would have been for me.
I am not really even sure how meaningful an email telling your coworkers to stop working on their projects is. It really depends on the tone. When I was at Google, I used the internal social media extensively. I am sure at some point someone said something like "I'm really depressed about how my project is going" and I would reply with something like "You should join my team! I have a req!" That's technically telling someone to stop working on their project, but is a completely acceptable thing to do.
Ultimately the exact details matter, and we don't have them.