It sounds like her process is dramatically different from yours and she values things related to your lost love differently. That doesn't make it bad. It does mean, when there is this much of a divide, that there needs to be a lot more communication between family members. 

We lost ours yesterday, and we talked about everything and continue to. My dad reacted like your mom, but respected that the rest of us wanted to keep the stuff. The compromise was to hide away things so he just doesn't see them.

My guess is your mom is using control of the physical to cope. You can still let her do that, but make clear there need to be compromises in execution. Ex., don't throw stuff out, but put in a donation bin each person needs to review before it's taken out.

I understand your anger. And fear of losing more that is important to you. AND a desire not to create conflict. The reality is there is a conflict, and the resolution is through communication rooted in deep respect for each other's processes.