Exclusivism diminishes God's perfection

https://alexanderpruss.blogspot.com/2009/07/pascals-wager-and-infinity.html?m=1

In this older post by Alex Pruss, the author wants to make the claim that, given Pascal's wager while weighing possible benefits and risks, it's more beneficial to follow a more exclusivist religion, giving Catholicism the edge over Islam. 

Putting aside the argument in the blog, the wager is of no interest to me. However it inspired me to make a short argument against exclusivist views of religion, which claims that only adherents of one religion or specific branch thereof are saved. 

Let's assume for simplicity sake that what Pruss writes is true, namely that Catholicism is rather exclusivist, while Islam inclusivist. We end up with this argument:

1) God, per definition, is absolutely perfect and can't be enhanced. 

2) An exclusivist view entails that God isn't forgiving towards false religious beliefs. 

3) An inclusivist view entails that God can forgive false religious beliefs. 

4) So the inclusivist God is more merciful. 

5) So the exclusivist God can be enhanced. 

6) Thus the exclusivist "God" isn't really God. 

This argument can be extended to make it in favor of universalism, but this is a topic for another day.