Leftists absolutely do vote
No they don't.
In 2022, younger voters made up a smaller share of the electorate than they did in 2018. In 2022, 36% of voters were under 50, compared with 40% of voters in 2018. Decreased turnout among these more reliably Democratic voters contributed to the GOP’s better performance in November.
Older voters turned out more reliably in both elections – and continued to be largely loyal to Republican candidates. For example, among adults ages 69 and older in 2022
Pew Research - 2020 election
If leftists understood how much power they have at local elections they would absolutely participate. Same goes for federal. But time and time again, they don't bother to be active politically because of attitudes like yours.