The longest lived fission products are actually the LEAST radioactive. This inverse relationship exists because of the fundamental relationship between half-life and radioactivity. The longer a radioisotope's half-life, the lower its specific activity (radioactivity per unit mass)
You are like a firefighter who opposes using water (nuclear energy) to extinguish fires (reduce CO2 emissions) because people might drown.
It is not a lie
https://en.m.wikipedia.org/wiki/Long-lived_fission_product
Wishful thinking on your part