@layman,
Your own quote tells us that you were referring to the present continuous.
Layman: You can do either. Fighting them "off" implies that you have won the battle. Merely "fighting" them suggests that the winner has yet to be determined.
You only made a distinction between the single verb, 'fighting' and the phrasal verb, 'fighting off', which advanced a notion that is totally false.
"Fighting them "off" implies that you have won the battle", does not hold the meaning that any battle has been won. It is no different than the meaning when you only use 'fighting'.
He is fighting off a cold. = He is fighting a cold.
Quote:The mere fact that a word ends in "ing" does not mean your usage of it HAS to be present continuous.
"We built a house, pounding hundreds of nails in the process."
It was NOT my usage, it was YOUR usage. You made the fictitious point.
What grammar point do you suggest your example sentence is illustrating?
"We built a house, pounding hundreds of nails in the process."