You're right but GTA IV also gets tons of hate the likes of which San Andreas and V doesn't get. People think it's boring or that it doesn't deserve the scores it got at the time. I disagree entirely, at the time there was nothing even close to it in open world with a modern setting. I'd even argue there still isn't since GTAV went in a completely different direction, tone-wise.
Having people hating it isn't underrating.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"