Help identifying this

Hello --

I'm guessing this is just some sort of rivet, but open to alternate suggestions. Pics attached of both ends. It is holding a bike rack cross mount together. In the picture, one end has a hole in it, but some of them do not.

Any suggestions on how to remove them? If it is a rivet, just gets drilled out, I think, but does it matter that it is about 3" long?

Once I have removed it and fixed the problem (some broken ratchet straps), what's the best way to put it back together? I have a rivet tool, but I think it is for much shorter rivets. Maybe just eliminate this fastener and use a nut and bolt setup...

Thanks!