That is one paper from a couple of postdocs.
60+: 86.1%
18+: 79.3%
12–17: 46.6%
Your only argument is not clogging up the ICUs. The only age group that has a significant risk is 60+, so isolate them or vax them or both. Forceful vaccination of 12-17 years olds will do exactly nothing for ICUs.