An activist is the guy who cleans the river, not the guy who concludes it’s dirty.

H. Ross Perot (1930-2019) American entrepreneur, politician, reformer [Henry Ross Perot, Sr.]

(Attributed)
    (Source)

In Ken Gross, Ross Perot: The Man Behind the Myth, ch. 14 (1992). A favorite saying of Perot's, varying slightly over the years (e.g., "The activist is not the man who says the river is dirty. The activist is the man who cleans up the river.").