Well that was... dumb. Did Gai really NEED a glurgy backstory to make him even MORE like Lee (depressingly by giving him a father JUST LIKE HIM only weak)? I mean god forbid that Gai actually come up with his life philosophy on his own as something to pass down to his surrogate son Lee, his own childhood had to be almost a carbon-copy of Lee's or CLEARLY there'd be no way he'd have been able to relate to him /sarcasm.
Interesting note, though- did you notice that when the Seven Swordsmen were confronting Gai's team in the flashback, the wielder of the dual Kiba swords WASN'T actually Ringo Ameyuri, the female swordsman revived by the Edo Tensei earlier in the arc, it was Kurosuki Raiga, the guy who actually died wielding them in the 'Curry of Life' filler arc of the anime? That means the character has now been canonised.