Giving up on the one you love (and who loves you back) for someone that is objectively "right" for you? How depressing. And unfair to this person you "settled" for.
True love defined ast overwhelming passion is very romantic. But the fact is that Oliver loves his crusade/revenge more than he "loves" Laurel, while Tommy actually treats Laurel with genuine love, which includes respect, even if that doesn't make her toes curl up. Oliver cheated on her with her sister. What Laurel feels for Oliver is romantic infatuation, not love. The relationship wtih Oliver that we've seen isn't a rich emotional life, it's just drama. It may be exciting, and it may be romantic, but it ain't love.