>>20957853it is never state anywhere in the manga that the spirit bomb needs the user to be pure of heart. Kaio just says to Gohan that he can bounce it back because he is pure hearted, and I guess someone jumped to the conclusion
Movie 7 SSJ goku can't use the spirit bomb cause SSJ turns him "a little evil" according to the daizenshuu 6 summary but that's about it. And this isn't canon obviously
