True, they did burn churches, but as you note, not with people inside. Tavington's (Tarleton's) "Green Dragoons" wearing standard British red has always bothered me, as has the formulaic nature of the plot, which turns the Revolution into a standard action film. I am also bothered by the explosive shells fired by the field artillery at the final battle (Cowpens), and by the film's approach to slavery.
By 1776 colonial attitudes toward slavery had hardened, thanks to Bacon's Rebellion in VA and the Stono River Rebellion in 1739 in SC, not to mention the New York uprising in 1741. In fact, after the Stono uprising, South Carolina passed a Negro Act, codifying slavery more strictly. Someone like Martin who freed his slaves would have been a pariah, if he were allowed to do it at all. Lord Dunmore's proclamation in VA, promising freedom to any slave who fought in the British Army, terrified southerners even more. Even Washington and Jefferson lost slaves to the British (Washington recaptured at least one, according to Joseph Ellis, in the aftermath of Yorktown).
As far as I recall, the film does show guerrilla resistance, but I don't remember a real neighbor against neighbor conflict. Everyone seems to be fighting the Satanic British, when even the vast majority of Tarleton's Legion were American Loyalists.
The film is entertaining, but it's not good history.