汉子 (son/person of Han) was - in ancient China - a term used by various people north of China to refer to the Chinese, but over time has been used by the Chinese to refer to themselves, and by the Qing dynasty, was already being used as a complimentary term for a "true" or "heroic" man, as in the terms 好汉 and 男子汉. The term is used to embody various masculine ideals, such as:
好汉不提当年勇 (A hero is silent about his past glories)
好汉做事好汉当 (a true man has the courage to accept the consequences of his own actions)
However, 汉子 (and its related terms) seem to be classified using 条, which is unusual because normally when 条 is used on people, it is derogatory, for example 一条走狗 (traitorous dog) or 一条豺狼 (brutal jackal). And yet it is used for 汉子, which is supposed to be a compliment:
京剧《黑旋风李逵》第四场：“我看你是条汉子，为何不投奔 梁山 ？”
So why use this particular measure word?