Robb gets so much hate and it's so unfair.

The Red Wedding was a perfect storm, and it's lazy to just say it's all because Robb married Talisa. Consider --

1) Robb wouldn't have had to treat with the Freys again if Theon hadn't taken Winterfell.

Theon taking Winterfell was ridiculous -- even Yara notes how stupid it is. As raiders, Iron Islanders had no use for a fort. Even if Theon always meant to go back to Balon, it didn't necessarily mean they'd attack Winterfell. Had Theon not attacked Winterfell, Bran and Rickon would likely have remained safe there.

2) If Theon hadn't taken Winterfell, news of Bran/Rickon's death wouldn't have spread and Catelyn wouldn't have released Jaime Lannister.

The release of Jaime Lannister is when it really all falls apart for Robb. Catelyn released Jaime because she wanted to secure the release of Sansa and Arya. By releasing the Kingslayer, the Starks lost legitimacy among the Northmen, which eventually led to Lord Karstark defying orders and killing the Lannister boy.

3) Talisa is hot af.

Seriously.