I've never seen a 7 foot Chinese guy, so it doesn't exist. I've never found any edge doing this or that, so it doesn't exist. It's not because you haven't found something, that it doesn't exist. Some make money using TA, some others say it's useless. Some make money using Elliot waves, some others say it's useless. Some make money with PA, some others say it's useless. Some make money with ML, some others say it's useless. Bottom line, you should have wrote: 'I have never found an edge emphasizing certain days over others'.
You only know toward the end of the week when it's all almost over whether what you have seen earlier that same week was a low or high that reversed.
Have you found an edge? I want to believe that certain niches are pretty easy to comb through in the search for an edge. This applies to verifying whether certain days of the week provide statistical advantages over others to trade certain direction. The number of possible realizations of events is finite and easily testable. I have done that work. Pretty exhaustively. Have you? But strictly speaking you are of course right. I might have overlooked something. I still firmly believe its a waste of time to dabble more than a few hours in testing and throwing such idea out the window...to each his or her own.
You know that, don't you? You come across as a know it all who don't know how much you don't know. Just because you didn't figure it out doesn't mean it's not there. The market's not random.
Yes, I've analyzed this stuff (days of week) extensively. And for the strategy/model I am using, Tuesdays are clearly not profitable (on average). I can understand that for others strategy/model, there are no differences.