Wikipedia has an extra page on that, which I took as the basis of my comment.
https://en.wikipedia.org/wiki/Mass_shooting#Definitions
To quote: " The term was originally defined as the murder of four or more people with no cooling-off period[1][5] but redefined by Congress in 2013 as being murder of three or more people."
Not only that, at the risk of repeating myself, the page you criticize as being "disingenuous" clearly mentions that definitions of "mass shootings" are controversial and provides 5 alternative definitions in the second paragraph of the article and then lists 7 data sources with definitions of "mass shooting" that either coincides with the one by US Congress or is more stringent (based on the pre 2013 definition).
The page also clearly states that "... only incidents considered mass shootings by at least two of the above sources are listed."
There is absolutely nothing disingenuous about this method.
What you and the people who downvote me cannot get into their minds is that there are official definitions that are used in statistics and that the listing on the Wikipedia page takes a slighly more stringent and narrower definition as a basis to safeguard against criticisms such as yours.
Again, you are of course free to re-define the term "mass shooting" differently from what e.g. the US Congress or Stanford University do, but this would not constitute a valid criticism of the list. How could it? Merely prefering your very personal definition over another one doesn't mean anything, especially if it deviates far from the official use of the term.