This is, imho, a very true statement.Spiritual realization unites people. Religion divides people. You will never be able to unite all the people of the world by identifying yourself as Bahai and hoping that everyone will convert to Bahai faith because people of other religions will identify themselves with their religions and may want you to convert to their faith and that is especially true of today's Islam and Christianity. Even if every person on this planet were to convert to the Bahai religion, it still won't guarantee peace and brotherhood without spiritual realization as evident from the differences and disputes between Abdul Baha and Mirza Mohammed Ali which they could never overcome because Mirza Mohammed Ali apparently lacked the spiritual realization to practice true brotherhood even with his own brother.
Personaly i would just formulate the first two sentence a little bit differently (only to make sure, that the term "Religion" stays in a neutral light )
"Religion without spiritual realization divides people. Religion with spiritual realization unites people."
Because of the two levels... you mentioned.
The outer level (physical, exo) and the inner level (spiritual, eso).
At the inner level a true Bahai is a true Christ is a true Hindu... and so on.
They are true if they really turned their heart to the one Sun (and not just only to the clothes of each ones Lamps)
The same Sun... from which - for example - Jesus and Baha'u'llah and Krishna was receiving their Light and Revelation.
Then there is no real division anymore. They also not must change the outer Religion.
They are connected at inner level to the living same source. To the spirit of Truth.
And the same source of truth... never every creates fighting and division.
And never did.
So that is, imho, the key to Unity.
It is not a matter of being a member of "the only true one" Religion... or Church. No. It's not. And never was.
It is also not really a matter of the outer rules (if they are all peacefull)
In the end... it is a matter to be in inner-touch... with the heart and mind and consciousness ... to the same source, called God.
Where all truth were ever came from.