For many people, sex is a way to "make love". Many people who are in love have sex as a way of showing their affection for each other. However, to teach "making love" as a synonym for sex, is to teach that someone showing unwanted sexual attention is in fact showing love. And that is incredibly dangerous both for our children, and for the rape culture we are trying so hard to eliminate.
The thing about love is that it is something that can be felt by one person and not the other and still be considered valid; you can love someone without them loving you back, and that is totally normal.` One thing about sex is that sex has to be a mutually enthusiastic thing, otherwise it is rape. It is with language like "making love" that people find ways to suggest that being sexually harassed should be conceived as "flattering" rather than "harassment".
The concept that a sexual drive toward someone and love for someone are one in the same is to give people the idea that sex is always warm and fuzzy. Sometimes it is not warm and fuzzy because we want it to be something other than that, and that can be rad, but sometimes it is not warm and fuzzy because it is assault, it is attack, it is quite the opposite of love; it is the disrespect of one's ownership over their own body.
You own yourself. You can have sex with someone you just like and don't love. You cannot have sex with someone who does not want to have sex with you. Making love can be sex, making love can be other things, but sex is not equal to making love.