What does NO and NOT mean? Why is this not a simple question to answer?

As spotted in comments on Breitbart article on writing checks for more checks in NY it's interesting to compare the fights in sexual matters where they say NO means NO aand then in constitutional matters it means WHATEVER WE WANT IT TO MEAN

The Second Amendment states;
The Right of the People to Keep and Bear Arms, SHALL NOT be Infringed... it does not include; except for those arms in the sole discretion of government to be prohibited to the people.