For what its worth my view is that people which support random walk dont look at the market as a whole they just look at price. Price is the end result of millions of decisions being made by market participants.
If you see a leaf falling down through the air and you chart its movements it will look like a toin coss chart. It appears random, but when you learn about aerodynamics, thermals, weather patterns, gravity etc the leaf's motions although still having random elements ( a car driving past) follow a predictable process. So do the markets
Just as a price chart looks random you have to put into context. take a currency chart, then plot interest rate differentials over it you will see a better than 50-50 (i.e random) percentage in favour of currencies yielding higher interest to trade at a premium. For those random walkers that accept price moves for valid reasons however all information is discounted instantly, there is nothing "instant" about the dollars recent demise. Could you "predict" the dollar was going to move like this? possibly. could you profit from the continuing dollar movements by realising that it was likely to continue until another another market force stopped it? almost certainly. What random walkers dont realise is that although a force to stop a markets movment could happen at any time doesnt mean you cant profit from calculating the probabilities of it happening