I have only seen the first episode of Kimi to Boku and am not familiar with Hetelia from memory, but Daily Lives of High School Boys is a prime example about how boys centric show would generally follow more raunchy themes. If the other two shows are different and genuninely show innocent themes, then I would call them outliers more than the rule. Same as with outliers to girls being depicted as innocent. Sure there are girls that play on the gap-moe bit those are the outliers (and lets be honest here, they are more often then not just there to deliver some innuendo joke).