Or maybe theres nothing different between someone here and in a different country.

People get upset everywhere. Upset people do irrational things. When the possible things someone can do include shoot every nearby person with a rapid fire rifle, then those will happen more often.

Other countries stab or burn or poison, but far less people are killed or injured.

I'll put it like this, you will never make certain every single person at every moment of the day does not act out in anger. As long as people act out anger in violence, they will seak tools to aid that.

Hence, guns banned by default with exemptions for those that need it, rather than the other way around.