Spoilers ahead for the target Venom .
Not much about Venom makes no sense. Why did it take the Riot symbiote six months to get to an airport? Why does Venom look like Spider-Man when the symbiote was never attached to Spider-Man How did Riot find Carlton Drake Why is the symbiosis sodifficult for other symbiotes to achieve, but not a problem for Riot, who can merge with anyone without a problem?
But the question that really asked me was why Venom chooses to sacrifice himself for humanity. The venom we know from most of the movies regards humanity as a source of food. Even its host, Eddie Brock, is both a great game and a great snack (what was Venom's plan after he finished eating Eddie from the inside?). Then, as the film nears its third act, Venom changes his mind. He confesses that on his home planet, he is a "loser" like Eddie, and that since he now loves Earth, he is ready to fight Eddie to save her from an impending invasion led by Riot.