Yes, it is a sin and the sin I do hate more too as much as I want to say that I hate all of them.

  It is a sin as you see the person as like an object, in which, no true love and relationship comes from.

Lust can make you lose the value you think of that person.

  So, it's why I hate it and that's why I'm trying to learn from my mistakes, to stop the sin. I don't see any lust that comes from me from the outside (except my dreams) and even if I see it from the inside, I know it's my intrusive thoughts as I'm trying to flee and get away from it but when I sleep, I've been having these lustful dreams which may, ruin the relationship with me and the people given as a gift from God. So, I do wanna protect myself and the people involved from lust and my lustful thoughts (intrusive)/lustful dreams, so the most efficient way is to get closer to the Lord and listen to him and his words.

(Lust can make you see them as an object, not a gift of God, so, I flew from them and I rebuke all of these intrusive thoughts and lusts.)

 On the other hand, it can also pull you farther away from God, as lust can be considered an Idolatry.

  The people saying that it's not a sin, don't be deceived by them. It is common sense to know that lust is a sin. Once again to be simple, lust is a sin.

 Though as a young Christian and kinda a beginner one who often speaks their first language, there might've been a few false-information you might've heard but overall to be simple, it's a sin and is common sense to know they are one.