I wish they would do those charts on a per capita basis. The slope looks pretty similar to other countries, but the scale on the chart makes it impossible to see. On the JH site, we look pretty similar to the UK. I also think its probably better to look at hospitalizations and deaths per capita at this point rather than positive tests. There's no way at 5% of the world's population that we're 35% of the COVID-19 cases. We've tested more than the rest of the world combined. At least with hospitalizations and deaths you have a higher likelihood of comparing apples to apples.
bwelbo, you may be interested in this site (LINK). I posted it a while back, but there is so much information going back and forth. I think it is the best way to track how countries are doing relative to one another. It tracks the progression of the ratio of new cases per week (or deaths) vs total cases (or deaths). It also uses a logarithmic scale to account for exponential growth. Those attributes account for both different relative start dates in different countries and different relative populations. It shows that virtually all counties start on the same exponential growth path, and which countries have been able to stop that and drop the growth rate off of that exponential path (and how quickly and how far). You can also select subsets of countries to compare one to another. For example, you can plot Finland, Denmark, Switzerland, and Sweden to get an idea of how much worse the growth has been in Sweden compared to those other countries, particularly its neighbors Finland and Denmark. (You can also ignore China if you want ; )
Here is a video that explains it in a bit more detail: