We Hate You Now. The Hardest Problem of the Aftertimes
medium.com
medium.com
New variants usually come from reservoir populations (animals), not humans. Slowing down the spread of a disease in the human population gives new variants time to develop, and also provides evolutionary pressure for them to spread despite the lockdown protections.
This is basic virology and population dynamics. This stuff is frequently taught in introductory college courses, if not high school biology.
The risk of introducing new variants was a well understood risk of the lockdown and was discussed early last year.