Over the past few months I've personally witnessed the bot continually undercutting other trades in order to force the price of bitcoins lower. This isn't a matter of just simple trading, the bot is actually forcing the value of bitcoins lower by preventing sales at current market values, and dropping prices to force the markets lower.
What you failed to deduce however is that in order to have any BTC to sell,
the bot has to continually over-cut other buyers as well so your downward pressure theorem just crashed through the window. All bots do is shrink the spread (that means more stable prices), it can't affect the price in any one direction long-term, nor is it in their best interests to do so. Your entire "analysis" completely disregards one whole side of the equation, and is therefore bunk.
What's pushing the prices down is the fact that the inflation isn't matching the growth of the market, and is actually outpacing it. No one seems to complain when the inflation can't keep up with the market, because everyone "gets richer" ($_$) it's only when the market falls behind people start whining and looking for something to blame.
That doesn't mean anything needs fixing, because it's fixing itself: If the market price keeps falling, that simply means it was too high.