WASHINGTON (Reuters) - U.S. President Donald Trump chided Merck & Co Inc’s Kenneth Frazier after the drugmaker’s chief executive resigned from a presidential advisory board earlier on Monday and cited a need for U.S. leaders to denounce bigotry following a violent weekend in Charlottesville, Virginia. “Now that Ken Frazier of Merck Pharma has resigned from President’s Manufacturing Council, he will have more time to LOWER RIPOFF DRUG PRICES!,” Trump wrote in a post on Twitter. 