One can argue that blurring the difference between NO and TLM and normalizing their coexistence in the same church is a way worse evil. As it would be to faithful to chose. Fr. Hesse warned against indult as well.
Fr. Hesse recommended against actually communing in the Indult if it was uncertain whether the hosts were consecrated in the NO or the TLM, but he actually said you *should* attend there if you don't have an SSPX to go to. He said you should go to the SSPX at least once a year to receive communion, and he said FSSP/indult sermons might be some small percentage unorthodox (which isn't a ringing endorsement) whereas SSPX sermons were reliable.
The idea that its leaving the Catholic Church to go to the Indult makes no sense and I don't see how someone who believes that isn't essentially making *themselves* to be the Pope.