It's not a misinterpretation, and he most definitely is being dismissive of faith.
But not faith in general. Picard himself previously stated that he believes (there's that word) that the spirit survives the demise of the flesh. That he would personally and intellectually continue in some fashion after his own death.
Picard says, "Doctor Barron, your report describes how rational these people are. Millennia ago, they abandoned their belief in the supernatural. Now you are asking me to sabotage that achievement, to send them back into the Dark Ages of superstition and ignorance and fear?
And this is the important part, Picard is specifically referring to Barron's report, the content of it. The result of the Mintakan's previous belief was "ignorance and fear."
Picard: "... the Enterprise crew currently includes representatives from thirteen planets. They each have their individual beliefs and values and I respect them all."
It's is absolutely impossible to imagine the multicultural Picard
as being generally dismissive towards all faiths. To the Mintakan's specific previous beliefs perhaps. But not all faiths, beliefs and religions.
Picard: "... and I respect them all
He clearly states that rational people abandon their belief in the supernatural.
Actually, Picard never does this, Picard (no doubt) considers himself to be a "rational" person, and again he does have his own beliefs.
Consider, we know that the first of the series of Prophet's orbs arrived on Bajor when the Bajorian people were already a civilized society with some technological. A culture of reasonable, sensible and sane people ... rational. This is the culture that came to worship the Prophets. The worship of the Prophets did not result in general "ignorance and fear." The Bajorian instead were a peaceful, artistic and religious people.
There is simply no way that Picard personally would be "absolutely dismissive" of the Bajorian religious faith, something that is so integral to who they are.