So I decided to finish destroying the old one just because I'm curious. I drilled off the heads of the bolt holding the arm on. Then I smacked it with a hammer until the epoxy broke. This took a lot of force. Here's what it looks like underneath.
The round hole is the one I drilled, but as you can see, there was already a lightening hole molded into the inner part of the swingarm.
I took a wire wheel to the swingarm to remove all the epoxy. Once the epoxy is gone you can go through the aluminum fast so it's a touchy process. After I removed all the epoxy and placed the arm back to the center section, there was enough slop that the swingarm would need to be placed in a jig to re-weld it. Clearly, trying to weld the arms to the center section is a failure on many levels and I won't be trying it again.
I also learned that this bolt is not removable: