Decades ago many Americans felt the same way about Catholics.
I can remember that being actually seriously discussed as an "issue" in the 1960 election. As a Catholic I found that argument absolutely bizzaro.
And then once JFK got elected and the world didn't end, that whole argument just magically disappeared. As if it never occurred to anybody that it was a stoopid argument to begin with.
My area is predominately Catholic and most of my family on both sides are as well. When I first learned of the anti-Catholic sentiment in middle school history I was gobsmacked. It seemed so silly and it still does. Foolishness.
Then there was the flap a few years ago about whether Nancy Pelosi should be denied the sacrament of communion on the basis of her abortion position, or something like that. I get the impression some people don't get the distinction between the practice of one's religion, which is a private matter, and what they do as an elected official, which is to represent and vote on behalf of the wishes of their constituents.