well, one reason so many don’t seem to understand this is because of how perverted and lukewarm to lust the world has become, it is very much conditioning and influence by society and by things like tv and computer and other things.
first of all, what does lust mean? the actual definition of lust is “intense sexual desire or appetite.” or “uncontrolled or illicit sexual desire or appetite”
that probably sounds wrong or not what you though of lust being, but that is it, sex is very much pushed right now, exploring your sexual desires, giving in to your curiosities, we’re told that these things are normal and natural, and that everyone experiences these things growing up and that it’s perfectly alright…well who tells us those things? good catholic teachers? good priests? nuns? the Pope? no, none of them tell us those things, try to remember who tells you these things, they are not Catholic…or atleast not good Catholics.
if you are catholic, then you need to listen to the Church, the Church is the only authority that Jesus left for us to learn our faith, Jesus gave the Church authority over our teaching so we would have someone to trust, and because Jesus told us to trust in and follow His church, then we can do no wrong and cannot be held accountable for anything we do in obedience to the teachings of the Church.
so what does the Church teach on sexuality?
well first off, they have never in history said it is wrong, sex is a natural thing we need for procreation, and it is an expression of love, God made it after all, so of course it is a good thing, but like all good things God has given us, it can be misused,
and unfortunately it is the most misused thing currently, so much so that people have been fooled into thinking lustful actions and imaginations are normal,
another name for the sin of lust is sins of the flesh, and they are in most cases the hardest sins to overcome, and will most likely temp you the rest of your life if you have fallen into them…there have probably only been a very small number of people throughout history who have not been plagued with temptation to sins of the flesh…
so as for lust, here is one of the catholic teaching on why it is wrong…
“Lust is an inordinate desire for or enjoyment of sexual pleasure. The desires or acts are inordinate when they do not confirm to the divinely ordained purpose of sexual pleasure, which is to foster the mutual love of husband and wife and, according to the dispositions of providence, to procreate and educate their children.”
so basically what we as Catholics believe is, the act of sex should only be preformed between husband and wife, and only in a manner leaving open the conception of a child.
why can’t we experience the sexual pleasures alone or outside of marriage?
well for one, we are temples of the Holy Spirit, if you were to masturbate for example, then you would be defiling the temple of the Holy Spirit, and isn’t that a rather shameful thing to do with Jesus inside of you? with your guardian angel watching you…if God didn’t mind the sexual pleasures being used this way, then do you think it would be a good an holy thing? and therefore priests could do it? or nuns? of course not…that’s just shameful and disgusting…
of course people want to have the sexual pleasures to themselves to use as they please, they feel good after all, but isn’t that why we all sin in the first place? because it makes us feel good…we wouldn’t sin if it felt horrible while we were doing it,
ok…to explain this alittle better, because i know i’m not answering your question very well, i’ll explain love…
first of all, love is not a feeling, you get feelings from love, but love itself is in the will, it is also charity, because it is something we only give, love is never taken, it cannot be taken, it can only be given, and received.
we show our love in many ways, but the greatest proof of our love for another is by sacrifice, love and sacrifice are almost interchangeable words, to say i love you without proving it is meaningless, if you are not willing to suffer for the one you love, then your love is a selfish one,
so, where i am going with this is, if you truly love someone, including God, then you would never commit sexual actions with another outside of marriage, and never with yourself, because God has said, not fornicators, adulterers, liars with mankind(and so on and so forth) will inherit the kingdom of God…knowing this, how could you allow the one you love to preform such actions? you basically say, “i love you, so lets go to hell together!” does that make sense? of course not…so when you love someone, but you feel these sexual desires, the only answer is to suffer in fighting them, when you can’t fight them or even refuse to fight them, then i think it’s at that point you need to question your so called “love” for the person you are with…so to answer your question specifically…
the reason the church has so much to say on what restrictions there are in regards to human sexual thoughts words and deeds, is because they love us! they do care if we go to hell, and God loves us more then anyone ever could, and He is the one who has told us of these sins, the church has not declared them sins, they have only taught them as such according to the word of God, the Church cannot ease up or change any of these sins because they have been revealed to us by God, and to change that would be in complete disobedience and defiance with God…so, i hope that helps answer your question,
but here are some reading materials for you that i’m sure will explain much better what you need to know…
columbia.edu/cu/augustine/arch/chastity.html
gaiaonline.com/guilds/viewtopic.php?t=13047641
ok, hope this helps, take care.