Good question. USA facts looks like it presents detailed data on a variety of subjects, so I don't think the site is fudging the numbers. My best guess is that the chart rates taxes according the sources they outline (property, fees, income, etc.). It would really help if we had a link to the source of the chart.

Here's a more comprehensive look at taxes state by state. Connecticut is not in the top 10 but is still high:

https://worldpopulationreview.com/state-rankings/highest-taxed-states

Here Connecticut is #7 highest in tax burden.

https://wallethub.com/edu/states-with-highest-lowest-tax-burden/20494

Connecticut is clearly not a low tax state, but where we fit in the overall rankings depends on the resource.