When Venom first saw Eddie, it was through Maria’s eyes.
Maria was homeless, and when you’re homeless most folks ignore you or treat you terribly. Some help out a bit and give you some change, but Eddie did so much more. He treated her like a person, a friend, and gave her much more then she asked for when she tried to sell him the free papers, even when he didn’t have much himself.
And when she saw him at the Life Foundation and cried for help, instead of backing away to hide, he risked getting caught and freed her.
Venom would have known all of this after a quick trip through Maria’s memories and would have seen how she saw Eddie, as a kind compassionate person.
So Venoms first impression of him would have been based on this, and since kindness isn’t much of a thing in symbiote society, there’s no doubt that Vemon was intrigued by this odd stupid human.