AR-15's are not assault rifles.  the AK-47's (the best model is the CZ USA VS 58)sold to the general public are not assault rifles.  Not really sure what you're problem is...unless what the rifle "looks" like scares you.  Is it because it looks like an M-16? (well, it should, as the M-16 WAS an AR-15 before the military adopted it, made some changes and designated it the M-16).  The civilian AR-15 came BEFORE the military M-16.  Or, could it be because it's black?  
To suggest that anyone owning a semi-automatic rifle that "scares" you because of the way it looks, makes them a serious threat to society is ludicrous.  It sounds to me like you  need a visit to a "Doctor" to find out what your problem is.  Because it's a serious one...and not based on any facts.