That's a fair criticism for sure. About a week before that peak, the governor also added in the closing of bars, indoor gyms, fitness clubs or centers, indoor movie theaters, waterparks and tubing operations. So, you can certainly imagine those contributed to the slow down, but as they only happened about a week before the peak they likely weren't the cause of the initial downturn because of the incubation time and testing delays.
Considering those were the only changes from the cases taking off and then peaking and slowing down it's definitely safe to say that closing high touch/close proximity businesses and masks have contributed to the ease of the spread.
However, you can look at other countries as they've reopened places like gyms and movie theaters. Many haven't seen a major rise in cases, but they do still require masks.