How would making election day a federal holiday increase voter turnout among anyone not working for the federal government. Plenty of federal holidays are working days for my company.
And plenty aren't... Many companies actually respect that every single company I worked at in the 10 years I've lived in America respected Christmas and New Year Day for example. I don't get your point, your situation is not the same as everyone else.
I'd actually be surprised if you worked for a private company and got every single federal holiday off. In 2016 they are:
Friday, January 1: New Year’s Day
Monday, January 18: Birthday of Martin Luther King, Jr.
Monday, February 15: Washington’s Birthday (aka Presidents Day)
Monday, May 30: Memorial Day
Monday, July 4: Independence Day (aka Fourth of July)
Monday, September 5: Labor Day
Monday, October 10: Columbus Day
Friday, November 11: Veterans Day
Thursday, November 24: Thanksgiving Day
Monday, December 26: Christmas Day*
Even growing up I had (public) school on Columbus Day.
Service workers work on almost all of them. Even the once sacred Thanksgiving isn't a day off for many retail employees anymore. Where I worked year ago they brought in low paid part time workers on holidays to cover for the full timers (who had benefits) who had the day off.
There's almost no companies that I know of that give off MLK Jr. Day or Presidents Day off. It's even a joke that only govt workers get those holidays off. Most places are not going to change their time off policy no matter what federal holidays are, if it's important for a company to have election day off they would already give it off, some official stamp of Congress isn't going to change anything outside of public office.