I used the analogy because of how people (parents especially) feel about war, and because its a thing that carries great risks of harm and exploitation, being a soldier. Of course there are circumstances where a parent, out of desperation usually (sometimes out of greed) - as a matter of survival - would be ok with it. But generally speaking, people who aren't desperate don't want their children to be soldiers, they want them to be happy, prosperous, not maimed, not violent and so on, so there has to be a lot of incentive and propaganda around it to convince people - and even then it finds a lot of resistance from people.

I know that soldiers are romanticized, and so is violence, but I don't think that because that occurs, education of children should be a free for all - gambling is another example, because its something that children (and adults of course, but that's a different though related issue) are vulnerable to taking a bad lesson from exposure to, that can lead to harmful consequences for them and others.

Sex is cool, but it can also be harmful, in and of itself or as an aspect of a relationship with others. War is similar - if a soldier is defending out of necessity their people from violence or theft, that's cool, but there is a lot of scope for it not being cool. Things like this, that have a great potential for harm and risk of harm, for individuals and communities, need to be treated very carefully and cautiously when it comes to children (and really, adults of course, but especially children). Despite sex being (usually) cool, its not I don't think an issue to request that teachers of children, as role models and authority figures, should not be pornographers - just as they should not be soldiers.