Again - you're picking only the bit you want for a racist narrative, albeit only a "slight" difference, and non-whites include more than 'black and Muslim'. Keep reading:

According to the Associated Press, white men comprise nearly 50 percent of all mass shooters in the US. According to the Center for Inquiry, mass shootings of family members (the most common) are usually carried out by White, middle-aged men.

Public mass shootings of persons unrelated to the shooter, and for a reason not connected with a previous crime (the rarest but most publicized) are committed by men whose racial distribution closely matches that of the nation as a whole. [eg. majority, white]