Why is "cult movies" translated as 邪典电(電)影?

I don't believe it has any connections with 经典. It must be a translation in a dialect, Cantonese, because areas like Hong Kong first met these type of films compared with other Chinese language areas.

A cult film, also commonly referred to as a cult classic, is a film with a cult following, obscure or unpopular with mainstream audiences, and often revolutionary or ironically enjoyed

The Chinese translation of 'cult' is '邪教', The Chinese translation of 'classic' is '經典

邪典电影 is short for 邪教經典电影 (cult classic films)

'Cult' in 'cult classic' denotes 'cult-like passion toward films that are deemed obscure, unpopular by the mainstream audiences

Obscure and unpopular is the trademark of cults.

'邪' in Chinese denote 'evil; wicked; heretical'

We should interpret '邪' in '邪典电影' as 'heretical' (from the mainstream audiences viewpoint)

We can describe '邪典电影' as a kind of non-mainstream film, enjoyed by a small minority of movies goers with a cult-like passion

Note: the term 'cult movies' is short for 'cult classic movies', But most people just refer it as 'cult classic'

In fact, the definition of 邪典 is something that can pollute a person's mind. But unfortunately you can't define 邪典电影 literally; its real meaning refers to some movies which some groups like, but is not universally popular. Usually these movies involve a director's subjective mind or their style is strange.

Fully translated, 邪典電影 is cult classic movie:

• 邪 = cult-ish/heterodox, c.f. 邪教 (religious cult)
• 典 = classic, c.f. 經典 (classics, classical)

In English, cult movie is really just short for cult classic movie.