Active Hate Groups Decline For Second Year

The Southern Poverty Law Center's report shows a decline in active extremist groups from 2018 to 2020, attributed to Donald Trump's presidency. However, this does not indicate a reduction in racist ideologies, as many groups have shifted online, especially during the pandemic, making them harder to track. Despite fewer groups, the threat level has increased, suggesting that traditional measures may not accurately reflect the current threat of violence. The SPLC has been reporting on hate groups since 1990.

Why might the current measure of extremist groups not be the most useful barometer?

What is the significance of the Southern Poverty Law Center's report since 1990?