Critical scholars who reject harmonization like to portray those who harmonize the Gospels as ignorant, rigid, and unhistorical. Supposedly this all arises from allowing one's theological preoccupations to cause one to engage in bizarre behavior (harmonization) that one wouldn't use in other contexts. Perhaps no one is better at giving this impression than Bart Ehrman, and sadly, it's an evaluation that has been internalized by some Christian scholars.
Today I read a quotation from Ehrman in which he makes his famous claim that harmonizing is "writing your own Gospel." He even goes so far as to saying that you're "robbing" the Gospel authors of their individual "integrity" as writers. He makes a question-begging analogy to overt fiction to support these claims and to set up the rigid rule of first impressions.
ehrmanblog.org/harmonizing-gospels/
Thumbnail photo by Dan Sears - Dan Sears UNC-Chapel Hill, CC BY 4.0, commons.wikimedia.org/w/index.php?curid=41276400