Hamlet lost the love of his father, mother, and Ophelia. Why is Hamlet responsible for this?in Hamlet
I edited your question down to just the first part because you are only allowed to ask one question at a time.
In response to your question I would argue that Hamlet didn't lose the love of any of those three characters. They were steady in their love for Hamlet until the moment each of them died. Hamlet's father was murdered by Claudius; Gertrude accidently drank poison that was intended for Hamlet; Ophelia committed suicide as a result of the deep despair over the death of her father and the state of her relationship with Hamlet. All of these characters deeply loved Hamlet -- there is NO evidence to the contrary on that.
Your question asked about Hamlet's responsibility in these losses. Again, I would say that Hamlet's responsibility is limited, especially in the case of his mother and father. Hamlet has absolutely NO culpability in loss of his father. Gertrude's death happens because Claudius is trying to kill Hamlet. I guess you could say that Hamlet's revealing that he knew about Claudius's murder of King Hamlet and his subsequent killing of Polonius brought on the end of the play with Laertes seeking vengeance and Claudius wanting to silence him, but that is kind of a stretch to then say that therefore, Hamlet is responsible for his mother's death. It could even be suggested that Gertrude drank the poison as a direct defiance of Claudius and that she was attempting to save Hamlet from drinking it.
The only character Hamlet is really in any directly way responsible for is Ophelia. Hamlet puts on his crazy act with Ophelia, leaving her very confused about the state of their relationship. When he realizes that she is being used by her father, he is rude and condemning of her, commanding "get thee to a nunnery!" She is heartbroken and confused when he is flirts with her during the play-within-a-play scene. When she finds out that her father is dead and that Hamlet is the killer, she loses her mind and drowns herself in the stream. Hamlet not being truthful with her from the start could be considered a cause of her death, and he is somewhat responsible for losing her.
I'll try to address the last portion of your question. To be honest, Hamlet isn't responsible for losing the love of his father; Hamlet clearly loves his father enough to (try to) revenge his murder, and his father obviously loves Hamlet because he chooses to seek him out beyond the grave. However, he does contribute to the feelings of lost love felt by his mother and Ophelia. He confuses Ophelia by his strange behavior in Act II.i when he comes to her room "with his doublet all unbraced...with a look so piteous in purport". Making it worse, he then chides her in his Act III.i "Get thee to a nunnery" speech, clearly antagonizing her, despite the fact that he is really acting out against his mother. Although Polonius has instructed her not to see Hamlet, Polonius continues to use her as a pawn in his attempt to assuage the tension felt by the King and the Queen over Hamlet. To continue with Ophelia, Hamlet also inadvertantly kills her father in his "madness" which further alienates Ophelia from him.
As far as his mother is concerned. He speaks frankly with her in Act III.iv forcing her to deal with her incestuous behavior and to hear the fact that her husband killed Hamlet's father. His rash behavior in this scence and the verbal jousts that ensue with the King over Polonius' body exacerbate his mother's concern for him. Despite this, I doubt that he "loses her love" because she agrees to avoid Claudius' bed at the end of his Act III.iv speech. His words leaves her heart "cleft in twain" and she asks for his advice saying, "Be thou assured, if words be made of breath,/And breath of life, I have no life to breathe/What thou has said to me." She drinks to Hamlet's success during his battle with Laertes, resulting in her own death. Clearly, he doesn't lose her love.
In Shakespeare's play Hamlet he weaves a tale of the prince of Denmark who is told by his father's ghost that he must seek his revenge. Hamlet's mother has married the man who murdered Hamlet's father.
Hamlet becomes a man obsessed and driven by his feelings of the need to avenge his father's murder. He alienates his mother because he identifies her as the traitor who has fallen under the stepfather's spell of love. This also makes him question his mother's role in regards to his father's death.
Ophelia has always loved Hamlet and believed that he in turn loved her and would marry her. Her brothers have mocked her and told her she was a fool for allowing herself to love someone who did not love her. Hamlet takes advantage of her love and pushes her away. Ophelia feeling desperate kills herself.