Is vegetarian oyster sauce vegan?

I heard that vegetarian oyster sauce is flavored with oysters? Then why do they call it vegetarian? I want to use Healthy Boy brand vegetarian oyster sauce if it is vegan, but I am not sure. Please, I need an answer to this questions pronto as I have some stuff burning on the stove waiting for me to add this last ingredient. Please no replies from hatemongers. I am asking this question here because I am a vegan. Also, would you date a person who used vegan oyster sauce?