The best revision for the claim as a rebuttal to the counterclaim is:
"Students usually study government and civics during the last two years of high school, so 16- and 17-year-olds find voting to be a way to engage with what they learn."
This revision addresses the counterclaim by highlighting the educational context in which young people are learning about citizenship and governance, suggesting that engaging them in voting at a younger age could foster lifelong voting habits.