The "other" races make up 8.9% of Reddit's U.S. userbase, but 33.8% on Braincels.
The most overrepresented races seem to be East-Asians and South-Asians, making up around 6% of the U.S. population, but around 20% on Braincels and around 13% on incels.co. These statistics correlate with racial fertility rates being 20% higher in Hispanics (notably Mexicans make up 63% of hispanics<ref>https://www.pewresearch.org/fact-tank/2017/09/18/how-the-u-s-hispanic-population-is-changing/</ref>) and 8% lower in Asians when compared to Whites.<ref name="statrace">https://www.statista.com/statistics/226292/us-fertility-rates-by-race-and-ethnicity/</ref>
Caveats which may limit the accuracy of the figures above: (1) Braincels is nearly exclusively male and may suffer other biases different from the Pew Research samples. (2) Latino includes Brazil, but not Spain, and Hispanic vice-versa.
(3) Some of the underrepresentation of Whites in incel forums may have resulted from bans of White [[alt-right]]ists.