Nowhere does it say they don’t recommend it. Just that they aren’t going to universally mandate it.
“For otherwise healthy 12 to 15 year old children, their risk of severe COVID-19 disease is small and therefore the potential for benefit from COVID-19 vaccination is also small. The JCVI’s view is that overall, the health benefits from COVID-19 vaccination to healthy children aged 12 to 15 years are marginally greater than the potential harms.
Taking a precautionary approach, this margin of benefit is considered too small to support universal COVID-19 vaccination for this age group at this time. The committee will continue to review safety data as they emerge.”