Surely you can find better sites to find the answer to this? There are numerous political writers who will tell you why. But I shall try to do you justice:
However as he's the Labour party leader, a traditionally Left wing party which has taken a more left-centre stance in recent years it's been in government from 97-2011 but he has more far left leaning views, some see him as a borderline socialist and his closest friends are on the extreme left wing of the party. No surprise he is hated by more right wing supporting people and also moderates.
From labour's point of view, the party is the largest in opposition to the government which means it is meant to hold a position of strength to speak against the government and attack their policies and Corbyn has been criticised for his effectiveness in doing this. I think the Tax Credit cuts being voted down was their only real victory in the house so far in opposition, even then they had a lot of Tories(Conservatives) rebelling. It's fair to say the SNP (Scottish Nationalist Party, which ironically hold liberal views) have been a far more effective party in opposition to the government.
Also from an electorate stand point - I know some labour party supporters who oppose Corbyn despite identifying with a lot of his political ideologies simply because he is not seen as electable in the next General Election, he is more of a Social Democrat than a Socialist , whilst the country in recent times has always voted for a party who's leader has more moderate stances, so they can appeal to undecided voters. Corbyn won't do this as effectively as someone like Owen Smith.
He also isn't universally hated, he remains popular with Labour Party members because of his politics and honest, calm approach to debate, and comes across as very caring of the voters needs, especially those who are on low incomes and welfare dependent. There is a sense that many politicians are out of touch of reality, which if you ever watch the PMQ's on a Wednesday morning, you would understand why they think this and why the appeal of a candidate with more civil manners is more appealing.
Hopefully I did you justice but he's not a popular choice among his fellow party members because he belongs to a clique within the party and is seen as unelectable by others. Meanwhile outside his party he is disliked for his social democratic views. And if you believe in it, many think there is a media campaign against him because he threatens those who are super rich and want to stay super rich.