I ruined my ex managers presentation
Why did you ruin their presentation?
Because I'm so angry with my current job
It is okay to be upset when things are not going well in a new job but you shouldn't take it out on your previous employers. It could get back to your current employers and you could get fired.
Oh but I found a reason to quit to so I don't care.
Even if you have already quit, your ex-manager may have prepared a lot for that presentation and you may have also put their employment in danger and I do not think you want that to happen. At the very least, I hope you have apologized to them.