Actually they ask "why" every time for every thing that I say :) My sons are not yet (to my eyes) sufficiently mature to really hear a thorough answer to "why". I try to make them asking "How?" instead. I'm a hacker, not a philosopher ;)
But, to relate to your answer, I'm not really trying to make them hating ads (thought I hate ads too, like you). Loving and hating things and people is up to them, I'm just giving context and knowledge (ok, sometimes it's hints on my own feelings on important subjects such as religion). That's of course a very personal pov on education.