Same problem here. I don't mind having OneDrive in the sidebar, as long as it knows its place. Which is alongside other cloud storage providers like Dropbox, iCloud Drive or Creative Cloud Files. And not promoted to the top of the navigation sidebar as an unfair advantage over its competitors, which are below the Quick Access list...
For me, the fix was simple. I moved the few things I had in OneDrive over to Dropbox and uninstalled OneDrive.