It’s totally arbitrary (as well as totally immaterial) whether the week starts on Sunday or Monday (or any other day for that matter). The fact that the US does it differently than many other countries really isn’t a big deal. Your downvotes show the whole bike shedding nature of the issue. The debate is so contentious because the stakes are so low.
I'm honestly not sure what "bike shedding" is but numerical values for days of the week very much count when building any software containing calendars (or any dates really) to make sure it works properly in different geographic regions.
