Earlier quoted context omitted.
Yeah but if you’re just syncing everything to and from a server anyway, why bother with it? Plus, rsync -a never deletes files.
Because you want syncthing to delete files more often than not. When you want the reverse, it's a single property on the shared folder (ignoreDelete), feel free to set it.
Is that ignoreDelete a Syncthing setting or something on the file system?