Well, saving yourself for marriage is an important factor, but it goes beyond that. It's the whole attitude regarding intimate relationships in general.
You are saying that making out is not a big deal, and sure, in terms raw physical actions, no, it's not a big deal. It's not like she's gonna get pregnant with some tongue action or anything.
But that's not the issue here. The issue is where does it lead and what kind of attitude does the person have about it? You think it's only going to stay as making out? Come on, are you THAT naive? Does a person who gets away with petty theft only stay at petty theft? I think not.
Even if she only wants to "stay at making out", you think the guy will? Don't you think the guy is going to be pushing farther and farther to try and get in her pants? And even if she's resistant to going all the way, she's going to compromise some things just to keep the guy...ok, so I won't have sex with you, but how about I give you a handjob...or even a blowjob instead. Wow....the whole "making out" scene has now turned quite sexual indeed.
YOU may not be able to see the big picture, but I've seen this scenario too many times to believe that this would be any different. But you know what? It doesn't matter if you believe what I say or not. Because when it comes down to it, it's only your own life you are messing up.
When in the future you aren't able to hold a steady relationship with anyone due to the countless times you took on casual relationships and now relationships in general have lost their meaning....and it takes more struggle than it's worth to try and maintain the futile relationship you're in? And then you wonder why so many marriages end in divorce? etc etc
I could go on and on...and it would only bore you. You people who think that YOU will be different...YOU won't let it happen to you. Well, have YOU won the lottery yet? Cause that's the kind of luck you're going to need to avoid this one when you're going down this path.
Sorry if anyone is offended by this...I just get very emotional when I see people walking towards problems...and I can't really do anything to stop it.