Point #2 is bullshit, there have been many mass stabbing events. Knife crime in general is also a problem. Same thing with vehicular killings. There are a number of high profile cases that have been in the news.
Point #2 you _consider_ bullshit, but are mistaken. It is a lot easier to pull a trigger than to stab. Murder still occurs, but at a much lower count per incident. The causal model holds: if you want lower mass shootings, restrict access to guns and ammo.
These are high profile because they are rare to accomplish relative to mass shootings.
The Buffalo shooter himself explicitly called out in his manifesto how much easier this act was to carry out due to his access to semiautomatic firearms.
These are high profile because they are rare to accomplish relative to mass shootings.