Humans ARE Animals after all.
But other then making babies, sex also feels good and brings you closer to your partner. Though yes, those who have sex with many different people isn't too smart, they have their own mind and body; not yours.
Also. Yes, more and more people are having sex and at younger ages as well. Yes keeping yourself from having a baby is needed for those too young to understand the time (and money) that has to be put in towards it, as it's a living thing that has to be raised to be another person in this world, unlike a non-talking dog.
Though there is nothing you can do. Your just another person in this world telling people "no" which is none of your business to begin with AND just going to make more say "yes".
On a side note; I'm 18, started my period today, and (of course; having to deal with this topic) had sex.
Do I want a baby in this point in time? No. But if I DID get pregnant I would raise it and keep it because that's the kind of person I am. I know the time and money it takes for a baby, as I have a 6 year old sister, 6 year old cousin, a 2 year old cousin, a newborn cousin, along with three of my friends who have babies that I help take care of along with my old coach's daughter (5) and son (1).
I love them all and their all very very cute. Would I want one to be my own? No. But if I had one of my own you can bet that damned well that I would raise it and make sure it grew up to be a real human, not some punk that everyone looks down on.