I have Abbey Road. I consider it one of the weaker Beatles albums, full of half-thought--out song fragments. Its shortcomings are not surprising considering it was the last album and that it was made as the group was on the verge of breaking up.
Lennon is right that some of the songs on this and other albums should have been pigeon-holed. (The White Albums especially contains a number of songs like that.) That's not surprising; when you produce as much work as the Beatles did, some of it is going to be not very good.
In general, Lennon did not like sentimental songs; he was a brake on McCartney, who was the opposite. (That's one reason they were such an effective song-writing duo.) I am surprised that Lennon disliked Lucy in the Sky with Diamonds. My fellow old people will remember the song was controversial because of the obvious reference in the title to you-know-what.
Yes, as
@RUPete says, many great artists are dicks. Many great *anythings* are dicks; there is no guarantee that greatness in achievement or talent goes along with greatness in personality. Maybe, in fact, there's a negative correlation because of the drive that's needed to be great in anything. End of sermon.