He's right. Fury may have lost an arm. He may hate Widow, but he's a professional before anything else. He's not the kind of guy who's going to let a personal vendetta prevent him from using a valuable tool. And let's be honest, Widow is the ideal character for that sort of team. She's the premiere super-spy of the Ultimate Universe. She's been working since the Cold War, has an extensive use of networks, and a stack of experience in the field. While the other characters you guys have put forth are professional criminals, they're just scrubs when it comes to the arena of international intrigue (with two possible exceptions. Mystique possibly could have some espionage background, and Beetle seems to have worked freelance, but I doubt either of them have the experience Widow does). The fact of the matter is, she's a perfect fit.
And I don't know. Ultimate Baron Zemo leading the team seems kind of silly to me, and Ultimate Darth Red seems even sillier. It makes sense to have criminals and self-interested spies blackmailed into working for the team, but I don't buy that these ideologically driven, passionate firebrands would make any sense as a government tool.