Microsoft deliberately blocks Affinity Thumbnails (.af) displaying on your PC

When syncing with OneDrive Microsoft deliberately blocks Affinity Thumbnails (.af) displaying on your PC.
 
After contacting OneDrive support, they admitted “This behaviour is by design”
It appears we are paying for a service where Microsoft select which thumbnails are displayed at Microsoft’s discretion.
 
Adobe files AI, PDF, PSB, PSD, Affinity’s main competitor are viewable as thumbnails.
Is this a corporate decision?  It certainly is not to the benefit of Microsoft’s paying customers.