"This is a main line of the King's Gambit. It's one of those lines that supposedly give Black an edge. "
well it does...but not so much of an edge that white couldnt outplay black if hes the better player. So its a reasonable choice especially if you think you are stronger than your opponent, or your opponent isnt familar.
6...bg7 was a strange move...the standard move is 6...g4, then ...f3 and later white has to sac on f3 to create an attack...and its rather speculative...but not terrible.
Can't White just undermine g4/f3 with h3?
Take a look at this little gem by Alexei Shirov!