Hello A Gooner, and nice to meet you. "Radical" can be defined as "favoring or effecting fundamental or revolutionary changes in current practices, conditions, or institutions." In this instance it is not being used pejoratively or as a critique, but rather an accompanying term to signify that his ideology at this time had become crystallized and in its post-Arbenz state, was indeed "radical". Che himself never shunned away from acknowledging the "radical" nature of the transformational Marxist world revolution which he believed was necessary, and in fact saw the term if anything as a compliment. Do you have sources or reasoning for questioning whether Guevara's ideology fits the definition of being "radical"?