I love cricket, but there's been a persistent series of match-fixing and spot-fixing allegations for years, almost exclusively originating from illegal south Asian (primarily Indian) bookmakers. The legal markets haven't been the source of this sort of problem at all.
Much as I might not like gambling, there is a persistent human desire for it and the evidence seems to be that banning it, as so often, exacerbates rather than minimises harm. The US government should stop trying to hold back the tide on this.