I looked at the articles you linked to. The New York Times mentions white extremist suggesting racially motivated but also mentions international terrorism instead of domestic terrorism. Your first source attempts to define right-wing extremism as a political motivation. That said your point isn’t very clear.
If you are limiting your point to domestic US terrorism racially motivated terrorism greatly exceeds religiously motivated terrorism but the numbers are tiny either way. If you are talking internationally religiously motivated terrorism by far takes the lead when you consider that ISIS is a growing threat in Afghanistan and Pakistan and when you consider the various terrorist organizations in sub-Saharan Africa like Boko Haram.
"Right-wing extremism" was clearly intended to refer to the home-grown variety here.
And how "tiny" the numbers are is somewhat subjective. Terrorism works by terrorizing, meaning its intended to affect far more people than the immediate victims by instilling fear.
Just from the last few years, everyone will remember the Orlando nightclub shooting, the Pittsburgh synagogue, the Q/MAGA-superfan mailing pipe bombs, or the Poway synagogue shooting. There are many more that you may have forgotten on wikipedia: https://en.wikipedia.org/wiki/Terrorism_in_the_United_States...
I am clearly reading from the material provided. Perhaps we have a difference in reading comprehension.
> was clearly intended
It is defined or it isn’t. I don’t like subjectively inventing definitions to fit a poorly framed argument.