The restrictions were uniformly unenforced throughout the USA. Enough people ignored them without consequence, so the pandemic effects were similar to states without restrictions. I live in CA, notorious for their "strict" stay-at-home orders and mask mandates. If I wanted to, I could have easily gotten in my car, violated those orders by driving around, found a restaurant violating those orders, sat down and eaten there, totally unmasked. If this was the situation in one of the "more locked down" states, then it's no surprise that the virus spread similarly to states where there were few restrictions.