When creating a view based on order products in ubercart, only people with access to all orders can see it
In the view's advanced settings, go to 'SQL Settings', and check 'Disable SQL rewriting'.

Drupal modules can hook in to SQL queries and alter them before they are executed. The Ubercart module automatically adds a permission check to queries that touch the Order table, to implement the 'view own orders' permission. Individual views can opt out of this rewriting mechanism, but that will prevent any module from altering the query. Be sure to thoroughly test that the view does not leak any sensitive information.