I don't think Urgot is evil -- he's simply not complicated enough to be "evil". He doesn't "stand" fpr or against anything because he doesn't have a purpose on his own.
He doesn't cause harm because he enjoys it, and he doesn't do it to achieve a greater purpose, selfish or not -- unlike Veigar, Vladimir, Viktor etc.
He's an empty sack of flesh and machinery, he can barely think in all of his pain, he can hardly breathe through all his machines, he can hardly walk on those legs.
He can hardly anything : pain is the only thing he knows, and the only thing he can deliver.
I'm not sure he'd react to the word "good" or "bad" or "evil" or any word.
When he was a human, possibly he could have killed someone for saying the wrong thing at the wrong time.
Now, the most terrifying thing about him is that his most violent outburst and his most tender display of affection would probably leave the recipient in the same state: mangled and torn apart.
I don't think he's intentionally harming people anymore -- revenge and pain is the only thing he knows. That's why he's a monster, whereas the other evil champions are (usually) not.