^Agreed.
You may not be present 24/7, but come on, you're responsible 24/7. My three year-old figured out how to change channels recently and as a parent I believe it's my job to monitor what he watches. For example, nothing with swears yet, but he loves superhero cartoons and usually starts flying around and beating up the evil villain (his little brother) after watching them. So we monitor him to the best of our abilities.
Parents need to take responsibility and get off their asses. My wife taught 4th Grade for several years and found numerous examples of parents who were too wrapped up in their own hobbies to take time to help kids with homework or even attend school functions. If you're going to have kids, check your selfishness.
This being said, I'm not perfect but I'm definitely trying my best. And it's really not hard to protect TV/internet (and yes, there are ways around it, but at least you made the effort).
3 Simple Implementable Ideas
1) If you have cable or satellite, you probably have parental preferences.
2) Set TV viewing hours in your house, and award extra time for chores, schoolwork, good behavior. (This is exactly what my parents did with me.)
3) Don't allow children to have TVs in their rooms if you don't trust their viewing habits.
/rant