Actually you're incorrect. Although the slope of the price (approximated by high order polynomials since the chart tends to be the limit of an equicontinous family of functions approximating the chart) may be negative, there are statistical arguments showing that such charts are intrinsically bullish. Example: Wedges, triangles, and other forms of consolidation. I suggest you get a copy of "The Encyclopedia of Chart Patterns" and review the statistical and empirical arguments showing that it is not as simple as a slope.
Also, variational calculus shows that extrema in a chart denoted by divergences are less probable than a classical configuration of normal trading. This is the mathematical underpinning of pinchers, channel breakouts, and BBand tightening. When such phenomena occur, the chart attains a state of low probability (a completed pattern) and thus changes behavior as outlined in the Encyclopedia as to attain a probable chart/configuration that we call a breakout. Example: Touch a lower BBand.
So, Clay is correct, but he doesn't talk down to people about the mathematical nuances of trading.