Here's something to think about. The entire concept of complete/incomplete information is flawed. There is no such thing as complete information. It doesn't matter if you're a scalper, day trader, swing trader, or long term investor, you will never have complete information when you make an investment. Even if you put your money in a savings account, you have no idea how inflation/deflation will affect its value. There will always be unknown variables.We define ‘randomness’ as incomplete information as it relates to data produced from market activity/markets.
Every investment imaginable carries some level of exposure to random unforeseen events. I'll agree with you on the basic theory that there is less randomness at higher time frames. I trust that US equities will go up during economic expansion and down during recession a lot more than I trust an intra-day trend to hold. But that doesn't mean that everyone trading at a shorter time frame is being fooled by randomness. It just means that the road to success is more difficult to travel.