Two things here:
1. In the eyes of many of the ignorant, all semi-automatic guns are considered "assault weapons". They believe that all semi-automatic guns will be banned under 1808.
2. This wasn't an accident. The plan is to report a ban of all semi-automatic weapons. When the uninformed learn that it isn't what happened, they will then become "outraged" and demand that it is corrected. Either the Marxists will claim it's the "will of the people" and we must do it or they will say it's the fault of the unwashed that it didn't happen.
Regardless, this is but a step in the process. We have heard all the drivel before, and as long as that pesky Constitution stands in the way of the Marxists they will continue to try to get around it.
Remember, the end game was spelled out by Barry O; to FUNDAMENTALLY CHANGE this country.