You can choose all and you can set that as your default if you are logged in.  We don't only do it for marketing but since some people ONLY want to see say cars or airplanes we tailor the site completely to those people and this avoids the noise if they have one interest area. 

the best solution is to stay logged in or choose your pref as you have been.  If we can make the selection happen without page refresh though we will look into that.