Looking back, I honestly thought it was Thanos who said it, but it's the Gardner who spoke so eloquently. But Thanos was involved.
It's one of the few rare instances, for among the similarities there are between Thanos (when he's great) and Doom (when Doom is great) is that Thanos knows what he is, he has few delusions about it, and has rare moments when even Thanos wishes he wasn't the bad guy.