There's really no avoiding this, since a non-existent Sacrament cannot DO anyting at all. Recall that a Sacrament is a visible sign that confers grace. So, just thinking about the visible sign, thinking about the Sacrament, effects justification? So it's because the Sacrament causes a thought about the Sacrament that the Sacrament causes justification?
It goes back to the modern, muddled mind, which started with subversive, occultic philosophers, such as Decartes. "I think, therefore I am."
BOD - "I desire baptism, therefore I receive it."

That's not reality.