Today (2nd May) is the 200th anniversary of one of the key events of the Peninsular War, the uprising in Madrid against French occupation. Napoleon's armies were eventually pushed out of Spain and Portugal by a combination of regular forces (the British Army under Wellington) and irregular forces. We now refer to such irregular forces by the Spanish word "guerrilla", which literally means "little war". Wikipedia defines it as "bloody, spontaneous fighting"; the comma is important.
[Wikipedia: Guerrilla Warfare, Peninsular War]
For some historians, attitudes towards guerilla depends on the context. From a British perspective, fighting against the Napoleonic Empire was a Good Thing. People who are instinctively disapprove of Empire tend to look favourably on guerrilla that opposes empire.
Indeed, the traditional opposition between Guerrilla and Empire leads some people to infer the existence of Empire from the existence of Guerrilla. "People are fighting against America as if it were an Empire, therefore it must be an Empire." This is a dangerous and invalid line of argument. Any argument about the nature of America must surely be based on America's own actions and aspirations, not on the actions of its opponents.
The traditional opposition between Guerrilla and Empire may also lead to either automatic approval of all guerrilla, or automatic disapproval. But that's like saying "All War Is Justified", "My Country Right Or Wrong" or "All You Need Is Love". Grand slogans, but no substitute for intelligent thought.
America's own stance towards guerrilla is complex and context-dependent: guerilla in Vietnam or Nicaragua is not the same as guerrilla in Africa or Soviet-occupied Afghanistan. Asymmetric warfare sometimes works in your favour; but as the British discovered long ago, powerful countries generally have more to lose than to gain from asymmetric warfare.
In the UK, intelligent but disaffected medical students often become comedians. In Latin America, a medical student became the glamorous face of the revolution, pinned up in countless student bedrooms, and now invoked as a fashion icon by people who have no understanding of politics or history. The purpose of guerrilla as marketing? I don't think so.