The ability to use whichever portal we want to access the database of addons will allow greater accessibility for differently abled people by allowing them choices. Monopolized entities historically have a poor track record of keeping the gates open for populations of people with greater assistance needs. I would prefer to see Curse allowing healthy competition, before we start to have an anti-trust situation in an arena where it would be hard to get official intervention.
Please reconsider your stance on not allowing WoWUp to share the addon database.