Interesting that a Morrissey fan would find Lennon repulsive - the two have so much in common.
Lennon was an anti-hero who made being scrawny, pale and sensitive heroic. He was willfully contemptuous of the mainstream in his solo work, and deliberately confrontational in his subject matter. He indulged in rabble-rousing of the very highest order.
In addition, Lennon had a terribly dry wit, sang with a voice that was at once aggressive-yet-vulnerable, and had an agenda of social change through art that I think Morrissey would have great sympathy for.
Most of all, both Lennon and Morrissey settled scores musically. They both trashed former bandmates in sarcastic, petulant song. I don't know who is the better musical whinger/score-settler - it's a toss-up.
As for not being a nice person, fair enough; Lennon was a hypocrite, but there are plenty of times when I don't think Morrissey is a particularly nice person, either. Really, both men come across as tempermental, difficult, and obnoxious on their worst days. Lennon left Liverpool to live in New York, Morrissey left Manchester to live in LA (for a while at least).
You don't have to like Lennon - many people don't, but he was a pioneering artist who actually made a difference, and who is fanatically loved by millions for a reason.