...so we all have to dress casual to make people feel comfortable? I don't think that's what you meant, but that's what you said. I think you're trying to be too much of a lawyer for the visitor that comes to the church. In their case, they will feel out of place for many reasons, such as everyone else carries a Bible, and "I don't know the words to the praise songs," etc... We've all been there. But I don't think any of us should feel guilty for putting on a dress or a tie or a sharp polo shirt and kakhi's or a clean shirt and jeans or whatever you might call "dressed up." We can't cover all the bases for what might put someone off -- we can't cater to every possiblity. Maybe we shouldn't carry Bibles, because that scares off the new people? (see the extreme?)
...and actually, some churches bend over too far to reach people, putting off quoting scripture, using secular music, talking about pop psychology instead of Biblical principles, never saying the name "Jesus," holding every known hobby class there is and only having one or two Bible studies, going on group outings to restaurants but never going on a mission trip, etc....You know what I'm talking about. At some point the compromising to attract outsiders has crossed a line. I think it's ok to dress up, but not of course to REQUIRE it.
I think the original discussion was about a heart issue. Casualness to God is the issue, not towards dress, and that's the point I think the author was making.