Eh, actually Vegeta is total bs. Goku telling Kuririn to let Vegeta live was based on nothing. AFTERWARDS, turns out Freezer and his guys would have won without Vegeta's "help", but Goku didn't know that and Vegeta might have just returned stronger. And later Vegeta casually murdered hundreds of people to provoke Goku into a fight. It wasn't until Super where Vegeta was castrated enough to no longer be a ticking bomb for everyone in his vicinity. And really, can he be forgiven all the genocides he committed when he destroyed entire planets with civilizations on them together with Nappa and Radditz? "He did it in Freezer's command", yeah, but he clearly enjoyed it a lot.
"Ad Hitlerium" is often ill applied, but in this case it's true: Vegeta is worse than Hitler. Would you forgive Hitler?