I'm sorry for putting DM as a source, but I can't find the quotes anywhere else as of now.
Article:
https://www.dailymail.co.uk/news/article-11609675/Prince-Harry-says-rowed-Prince-William-BEARD.html
We're getting here a few interesting things about the wedding. I tried (and failed) and tried again (unsuccessfully) to find any sort of logic in this. Discussions about venues:
If this conversation is indeed true, I cannot imagine how difficult it was to deal with Harry at that point in time. So the choice was Westminster, St. Paul's or eloping in Botswana? Harry is moving in the extremes - it either has to be the biggest, most prestigious venues or eloping? If eloping/small wedding was the prefered choice, why a small church/cathedral was a problem?
What I see here is William trying to find a solution that would make his brother happy, not knowing, or maybe even knowing, which is more sad, that there's no making Harry happy.
The satisfaction of one-upping his brother on something that minor is glowing from this paragraph. But I have some serious doubts about Harry's interpretation of the situation. William (and Catherine as well) know the drill - do or don't do some things to keep the peace, to not rock the boat. Shave for the wedding and avoid having 10 articles written about it. To me it sounds like William, once again, trying to protect his brother.