You are rationally correct. However, most people react very quickly, and it is very effective to say "teenager" or "25 year old" to mean "ridiculously inexperienced" for what is happening right now

Yes, some teenagers and 25 year olds are capable, and probably do in fact, write system-critical code

But having people who previously had nothing to do with the government, take over a federal system, with seemingly no experience managing those types of systems before, is very alarming