Asking permission to bring a date, is not only bad manners, in the extreme, but would be rebuffed by most. Unless, of course, it was a rather informal wedding and done on the cheap.
I take it that you have never been married/planned a wedding and have no idea what the correct etiquette is.
I can understand and agree with you if you are talking only about the wedding reception after the marriage ceremony, but to attend a wedding ceremony in a church, come on now.
I am married and I was involved in the planning. We did not put any restrictions on the church wedding, (come one,come all to share in our joy), but we did limit who was invited to the reception, because of the money involved.
Almost all of thr wedding announcements I got when I was single said "Mr. Freedumb2003 and guest."
Many of them were of that middle size where I think strangers could have infiltrated and no one would have known.
In California there are a lot of outdoor weddings and they are hard to "control."
Maybe all these strict rules I am reading on this thread are regional?
My personal opinion is that if the bride's parents wish to invite guests, it is perfectly permissible to do so. Showing up uninvited, however, is not.
You are quite the snob.