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You're missing important stuff here, most notably that recommendations are also based on availability. As the vaccine became more available, more demographics were recommended to take it. Obviously, in the beginning, you want the highest risk groups to take it, then you grow the radius.

They didn't use young girls as some safety experiment. They just had the largest benefit and so, in scarcity, they're prioritized. It's not that scarce anymore.

As an aside, the HPV vaccine also prevents some male cancers, like penile cancer. It also prevents cosmetic, but relatively safe, conditions - like genital and anal warts. That's not the goal of the vaccine so it's not really taken into account. But you, someone who may take the vaccine, should consider it anyway.