The markets are forward looking
The markets are forward looking
The markets are forward looking
What this means is that IF it looks like Fauxcahontus is going to win, the sell-off will happen before the election. (It's very possible that Obama's likely election may have been the impetus for the collapse just prior to his election, for example. Note, there were a lot of other factors in that crash, and it would have happened eventually, but his impending election may have been the trigger.)
Because Trump's election was a surprise to almost everyone, it wasn't already priced into the market. The market, in fact, had priced a Clinton presidency into their calculations and, as a result, when an unexpected GOOD thing like Trump getting elected happened, the market had a LONG way to go to react to that.
The people who said the market would crash were just wish-casting. Investors know which party will be good for growth and react accordingly.