Whatever you think of the subject matter -- the re-creation of late medieval and early modern martial arts starting with the surviving treatises from the period -- Back to the Source is quite an amazingly good documentary.
I have enough experience of the earliest SCA and its later evolution to recognize the attractive glow around people who are inventing something from early exemplars and creating a dream -- and creating a community in which the pioneering impulse is very strong. Some of the interviewees worry that as HEMA progresses and becomes more standardized -- in other words as the pioneers teach a more sophisticated art to a large number of people -- something will be lost.
Sorry, folks, this is guaranteed to happen. You will attract people who want to practice "sport for sport's sake." Some of them will care a lot more about winning than recreating a historical art. Where pioneering HEMA members of today may respect scholarship as much or more than winning, a large, developed HEMA community will include plenty of people who value winning and winners more than the historical purists.
Enjoy it while you have got it. Whatever your particular "it" is.