That source is so unreliable that you may want to check those "claims" yourself, by hand:

https://en.wikipedia.org/wiki/The_Washington_Times#Controver...

Likely better source that disproves the "claims" in the article above, since perp demographics are in line with the male demographics of the US:

https://en.wikipedia.org/wiki/Mass_shootings_in_the_United_S...