Why does no one talk about the wildly inappropriate relationship between the eccentric elderly scientist Dr. Emmett Brown and high School teenager Marty McFly?

From the Back to the Future Wiki:

“Gale and Zemeckis conceived the idea for Back to the Future in 1980. They were desperate for a successful film after numerous collaborative failures, but the project was rejected more than forty times by various studios because it was not considered raunchy enough to compete with the successful comedies of the era.”

Marty gets stripped to his tighty-whiteys by his teenage mother and come onto. Not raunchy enough. Okay.

Also get this. Marvin Berry and the Starlighters are a fictional band, BUT
There is a real band that was big in the 60’s called Joey Dee and the Starliters. Their first single was a song called “Loraine” which is the name of Marty’s mother in the film.