When homosexuality was mentioned in films, it was used as humor, fear and pity. It didn’t help that Hollywood influenced us on how we perceive homosexuality. For gay audiences, they believe that something was wrong with them and for straight audiences, they had stereotype(s) in mind after watching the said film; Ex: Gay people act feminine
Unfortunately gays and lesbians characters are still (sometimes) depicted as the joke in the film or that the audiences/film makers still attach some type of stereotypes to them.
Censorship is another problem in Hollywood when it comes to lesbians and gays. It got bad enough that it caused an uproar and scripts had to be changed.
Example: Queen Christina- it was based on a real life Swedish monarch and that Queen Christina is a lesbian. When Hollywood picked up the film, they change the film dramatically.
However, many film makers/ screen writers sneak a few hints here and there that might go unnoticed by an untrained eye.