Is Romeo and Juliet a love story?
In part, yes. It's true that Romeo and Juliet are incredibly young, that they fall in love incredibly quickly, and that they behave rashly and recklessly at times. I do not, however, think Shakespeare belittles their feelings or implies that their feelings are invalid simply because they are young. Although some might scoff at their naivety, their feelings for one another feel incredibly real to them, and I think Shakespeare builds tension through his use of dramatic irony so deftly that the audience cannot help but be tugged along through their misfortunes with them. Dramatic irony is when the audience knows more than the character — its purpose is to build tension in the play — and one of the most important examples of dramatic irony is the final scene, when we know Juliet will wake up at any moment just as Romeo sips the poison that will kill him. If Shakespeare's intention was to satirize a contemporary obsession with romance, then he's gone to awfully great pains to make us feel the desperation and desire they feel.
Further, Romeo and Juliet are, in many ways, mature. Romeo is rightfully angered in the beginning when he learns of the street fight, and, though other boys his age are acting aggressively, he does not. Then, he initially refuses to engage Tybalt, speaking calmly and rationally to him in an attempt to defuse the situation. Likewise, Juliet is resolute when she makes a decision, exhibiting great bravery in standing up to her parents who don't treat her very lovingly, as well as being willing to fake her own death. These two aren't characterized as ridiculous; Shakespeare affords them and their feelings a lot of respect in the play.
At first, it seems obvious that Romeo and Juliet is a love story. However if you dig a bit deeper into the plot, there is cause to argue that Shakespeare has written a satire depicting the surrounding culture's obsession with romantic love and the consequences which come from it. For instance, the entire play occurs within two to three days, in which Romeo and Juliet meet, fall in love, are married, are separated and then both die. Even some of Romeo's lines depicting his love for Juliet are comical in the fact that he hardly knows her within this time limitation. The two feuding families have produced spoiled and somewhat neglected children, and though Romeo and Juliet are considered old enough to be married, they reveal their immaturity throughout the play. Romeo reveals his reckless heart in the opening scenes, when he is lovesick for Rosalind but immediately forgets his woe when he sees Juliet, who happens to be her cousin. Romeo emotionally manipulates the friar, whom he usually seeks advice and wise counsel from, by throwing a fit so that the friar will marry him to Juliet against his better judgment. These are only two instances which show the selfish nature and immaturity of Romeo, and when compared to a traditional love story, he is an embarrassingly bad protagonist. Most protagonists of love stories, even in Shakespeare's era, are heroic and have some type of character trait which others cannot reach, thus making him desirable. Usually these protagonists have amazing courage, or unshaking honesty which causes them to stand above the rest. Romeo has none of that. All of these evidences lead to the conclusion that he is a mock-protagonist in a satirical love story which is not to be taken seriously. Rather Shakespeare wrote to warn people of the tragedy which an occur out of situations which never needed to happen in the first place.