The difference between both culture and law leads to different situations in different regions. Private possession of firearms is legal in the United States, but this is a felony until the death penalty in China. Freedom of speech is common in democracies, but it doesn't work here, and certain topics are officially banned. Twitter and Youtube, the most active web site in the world, are banned in China.
However, even in the US, it is illegal to use firearms for intentional wounding. Similarly, hurtful remarks are forbidden. Including racial discrimination, national discrimination, personal attacks and so on. Besides, trolls are disgusting.