"Quite simple really: jealousy and ignorance."
Not in a thousand years Cap'n
MacColl and Dylan as performers and in objectives were chalk and cheese - they were coming from different directions and Dylan changed course in mid-stream anyway and totally abandoned the tradition in pursuit of the big bucks - and made no pretence of doing otherwise.
Whether you prefer one or t'other is a matter of taste - personally, as much as I agree with people's comments on some of MacColl's more ephemeral pieces, which were songs for the moment, not intended to outlive the events they covered, I believe songs like Freeborn Man, Shoals of Herring, Dirty Old Town, Joy of Living - and many, many more (even Sweet Thames) will, still be sung long after all here have joined the 'choir invisibule'.
I've never really understood why 'First Time Ever' surfces in these discussions - it certainly was never, or never considered to be - one of Ewan's best songs, by him or anybody else. Both he and Peggy were staggered and, I believe, slightly embarrassed when it 'made it big-time' though it did allow them to set up Blackthorn Records which, IMO gave us four of the best albums of traditional ballads ever.
Personally, I found Dylan's first few efforts mildly interesting, but they soon faded and his later stuff became jaded and poetically pretentious.
As a protest singer, Dylan will always be - for me anyway - the rising star who refused to join Seeger and the others on the Civil Rights Marches because he "couldn't afford the fare", until he was 'made an offer he couldn't refuse' by singer/actor Theodore Bikel - a free bus ticket South.   
"Wasn't it a little bearded Scottish guy that shouted 'Judas!'"
A similar incident was reported following Dylan's appearance at Newport - the offended party was said to have been Pete Seeger.
As a 'folk' performer Dylan was somewhat disregarded by MacColl and Lloyd, and other figures in the revival, their main concern being that he might get in the way of singers exploring their own traditions - Alan Lomax's idea originally - thankfully he didn't.
Jim Carroll