They had been rising quickly before any of the protests took place and are linked with various states "opening up" too soon. Philadelphia, for example, is not, to my knowledge, seeing an increase in cases despite large protests 2 weeks ago. My wife works for a big hospital in PA and they haven't seen increases in the number of covid cases on their daily census - it's been slowly declining for over a month. Pennsylvania itself was pretty quick to lock things down and has been on the careful end of opening things back up and still has various mask requirements even in regions that are in the "green" phase. States such as FL... not so much.
How Covid was dealt with varies drastically state to state. Some states, particularly those in the northeast had a more dramatic reaction, while others barely did anything. The latter are where cases are going up quickly.
...I'd be willing to buy that if there were any sort of uniformity in terms of "states opening up sooner vs staying locked down" with regards to outcomes.
It's easy to cherry pick an example of a state governor one doesn't like that's having an issue with it, and using that to form a narrative.
The reality is, you can find just about any combination you're looking for...
California and NY are both strict: NY is greatly improving, Cali is getting way worse
Ohio, Florida, Colorado, and Texas were all on the more lax side: Ohio and Colorado are doing okay...Texas and Florida, not so much.
If it were as simple as "reopening = disaster" "locking down = stability", then NY & Cali should be having similar outcomes, and Ohio and Colorado should be having the same issues as Texas and Florida.
For the record, I don't think it's a coincidence that Colorado's governor being a democrat and Ohio's Mike DeWine a "blue-friendly" republican were the reason why a lot of the left leaning media didn't attack them for re-opening the same way they did Kemp, Abbott, DeSantis. (even though the strategies were all nearly identical with the exception of maybe 7 days difference in the phased re-opening initiation)
Obviously re-opening and increasing testing rates are going to lead to increases, that's a given.
However (and I elaborated on this in a previous post), there other factors that I feel are larger contributors with regards to reasons why some states are doing okay and others are having serious issues.