Ignore all the errors, the deceptive use of numbers, and the emotional appeals. There is one sentence that explains why they just don't get it:

America is a nation that pays a heavy price for permitting its citizens to be armed.

Our constitution does not permit its citizens to be armed.

Yup. You read that right. And that is not an late April fools joke either.

Until they understand and adhere to this fundamental point they will never understand or leave us alone. The reality is that the people had the right to be armed before the Constitution existed and the people retained, explicitly through the 2nd and 10th Amendments those rights afterward. The U.S. Constitution permitted, through Article I, Section 8, Clauses 15 and 16, the government to be armed.