Jupiter12

If it's substantially damaged yes, I wouldn't exactly trust a NH-D15 class of air cooler with it for example

Since you can still screw the standoffs in, if you can flatten out the holes in the case you might be able to apply some loctite or epoxy to the standoffs before you screw them in to give it some extra strength.  Just make sure you line everything up with the motherboard first because, especially with epoxy, they will probably not be coming out again.

Ambient humidity isn't going to affect the loctite or epoxy but if there isn't enough thread to get a bite with the standoff I wouldn't trust either to hold the standoff in an open hole for any length of time.

Just.. What? With those pliers you could have like.. Unscrewed the standoffs?
 
If the case frame wasn't bend, you could have people fitted in the original standoffs (or bought some in bulk from Amazon or something) and installed them using some nuts on the other side. The case being bent like this would make it quite difficult to install the .. What is it, 9(?) standoffs required for an ATX motherboard.
I just hope the close-up picture you showed are the standoff positions with the worst damage, because if so you might be able to place some wood behind it and kind of 'love tap' the metal flush again.
 
This is gonna need some mechanical fixing up and then you have to hope you can install it all.
 
Good luck.

Given how those mounting points on the picture look like you won't be able to salvage that easily, if you ripped the standoffs out of the board, aside of bending the metal you most likely also damaged the threads inside, so even bending it back is unlikely to work.
 
I can't wrap my head around how you even came to the idea of ripping them out when you could have simply unscrewed every single one without damaging anything.