How are lotus eaters a threat ?

The lotus Eaters were high all the time from eating their plant, most likely opium derived from the poppy. I think the biggest threat was Odysseus's men not wanting to return to the ship because they were obsessed with the narcotic effects of the "lotus".

The Lotus Eaters were a threat to Odysseus and his men because the effects of the Lotus made them not want to return to the ship.