I normally surround the word "assault" with sneer quotes whenever it's used to modify the word "weapons", since all weapons are inherently and exclusively intended for the purpose of assault, rending the term "assault weapons" redundant. Imagine if we always used redundant phraseology like "writing pencil" or "food spoon" - it would be a little inefficient.
While it's true that anti-self-defense advocates invented this terminology to advance their political agenda, the creators of this website, in good faith, avoid the hyperbole and sarcasm that so many of us find difficult to contain (note my hyperbolic use of the term "anti-self-defense advocates"). They present facts and figures, some of them directly from Senator Dianne Feinstein's own press release announcing her proposal of anti-self-defense legislation, and they clarify what a real assault weapon actually is. They distinguish from true assault weapons the type of gun that anti-self-defense advocates have attempted to define as an assault weapon, and show that it accounted for 0.6% of all murders committed with guns in 2011.
The fact that these people seek to ban this type of weapon clearly demonstrates their cynicism. They're not even truly interested in stopping deaths, otherwise they'd seek to ban handguns, swimming pools, and automobiles, all of which cause vastly more death than assault weapons, as defined by these advocates or otherwise. One might speculate that their true motive is to initiate some momentum in support of their agenda in hopes of eventually banning all weapons. One might also speculate that their ultimate goal in doing so is to completely disarm the American people, shifting the balance of power completely to the government, since they trust in government more than people. But that would all be just speculation . . .