Before giving his own answer, Krishna lays out the debate. One school of thinkers says: all action is flawed by nature, so give it all up. Another school disagrees: acts like yajna, charity, and tapas (austerity) are sacred — they must never be abandoned.
This is an honest presentation of a philosophical disagreement that existed in ancient India. Some traditions held that any action, no matter how noble, traps you in the cycle of karma. Others insisted that certain duties purify the doer and must be carried on.
Krishna does not dismiss either side here. He simply places both arguments on the table. His own definitive answer comes next — and the Gita's teaching method shines through: first the question, then the debate, and finally the clear verdict.