I can understand the distinction that making Election Day a national holiday, replacing Veterans Day, is disrespectful to Veterans. I can also appreciate the writer's notion that doing so would lessen the meaning of Veterans Day and would essentially make it 'Politicians Day'. However, were this to become a national holiday, I am not convinced this would benefit Jackson Lee's interests.
As you mentioned, theoretically, this would get more Americans out to the polls (as they would have a day off from work). IMHO (and my compass could be way off on this subject, I'll not argue that), the more working Americans at the polls, the better for the GOP.