Jim,
Go and read what she has to say instead of looking of out of context clips

I have, and my quotes are wholly representative. They are NOT "out of context." I supplied links so they can be seen in their original intended context.

she goes on to say immediately after that that the reasons for joining were far more complex

No. She says that they were "more complex" than your "myth of war enthusiasm would suggest."
It is YOU trying to put quotes out of context!

Dave,
What proportion of the general public were less than enthusiastic about the war?

Not enthusiastic. They just believed it had to be done.
Paxton said "most people."
MacMillan would not have said, ""Britain certainly thought" unless she knew it to be most people.

Pennell clearly meant most people or she would not have said, "the public rallied around what was perceived as a just cause." and " People supported the war, but only because they felt it was the right thing to do in light of the circumstances."

Most people Dave, and right to the end of the the war.
Most people Jim.
The myth you cling to is debunked and discredited, not by me, but by hard facts and hard evidence researched by leading historians who head university History Faculties.