Most people believe in God,

The popularity fallacy is not a good argument.

you’re arguing most people are being swindled, implying they are not intelligent enough to come to their own conclusions on the existence of a higher power.

Non sequitur. Being swindled doesn't denote lack of inteligence, but a lapse in critical thinking (or the lack of it) in the particular topic of the existence of gods. Everybody is vulnerable to lapses of critical thinking, specially for those believers who are part of communities where doubt is portrayed as dangerous and the tools for critical thinking are not only not provided but discouraged.

That is a very pessimistic view of reality I think

It would be if you didn't misrepresent my position.

people such as Galileo, Darwin, and Newton were very religious themselves.

Galileo lived in a time where not being religious incurred risk to one's life, so mentioning him is unfair.

Again, being religious and being intelligent are mostly orthogonal propositions. Critical thinking requires exercise, though, and when unused, it can atrophy. Or be totally non-existent if never taught.

If I were to quote intelligent celebrities as "proof" that religions are true (a doubtful procedure in any case, as it's an authority fallacy), I could mention Francis Collins, director of the National Human Genome Research Institute and current science advisor for president Joe Biden. He's deeply religious. But he's not using the scientific method to reinforce his belief. And he's not less intelligent just because he's probably mistaken about the reality of his god.