Non-Gendered Acting Roles

No other job category requires a gender.

Really?
That cannot be farther from the truth.
Here's one
WNBA Player.
Here's another.
Entertainment Jobs

Many stage and screen acting jobs and jobs for dancers and singers require you to be a man. Producers and directors often desire to create a sense of believability and genuineness in their products, and it would be less believable for most audiences if a woman played a male role. In other cases, entertainment jobs are male-specific because the employer is specifically providing a product or service that requires men. For example, the Chippendales franchise caters to women who wish to see men performing exotic dances. Thus, Chippendales only considers male performers. Some fashion model jobs also are male-specific since they involve modeling men’s clothing and accessories.

Another

Bathroom Attendant

Upscale or trendy nightclubs and restaurants sometimes hire attendants to work in bathrooms. These bathroom attendant jobs require workers to be of the same gender as people who will use the bathroom. Thus, half of all bathroom attendant jobs are available only to male applicants. Some locker room jobs and janitorial jobs may also be male-only positions since the jobs could require employees to work in locker rooms and bathrooms where only men are allowed.

Another

Catholic Priests

The Catholic church does not allow women to join the priesthood. Only men may be ordained as priests, and only men can serve as deacons in the Catholic church. In 2013, the Catholic church employed 39,600 priests. In 1994, Pope John Paul II formally stated that the church does not have the power to ordain women. Some Catholics believe the church will change its position on women joining the priesthood.

Obviously each professional should provide that information in the manner she or he wants. For the great majority of users of this or other sites, what you call gendered acting roles are a great help.
In Spain where I live, there have always been ACTRICES and ACTORES, and few people would have it any other way. Plus we have Presidentas, directoras and so forth.
The same goes for other European languages I know.
No-one should feel slighted by this, but if they do, let them just 'do their own thing.'

Amelia, problem goes both ways. Arguably word "actor" is non-gendered, per se, but many perceive it as, traditionally, a "male" word and argue that we crucially need feminitives, because original words are implying that professions are dominated by men. 

In Ukraine, for example, feminitves for most professions were just recently introduced, so we do have a feminitve for "director", among other things. It is considered by most a progressive move, so it's interesting to see that the very opposite is in demand in an English-speaking world. Although, of course, there are specifics attached to this situation in acting, which could merit for its own book or article. 

I do think that the middle grounds and other options are needed too and for multiple reasons: many times while adding names from end credits there are some cases which need further re-checking in terms of gender and that still might not help, leaving contributor with the only option of assuming actor's gender, which is not exactly a great thing on many levels.    

I'm guessing not everyone wants the gender removed from their profession. It's going to take a while for sites like IMDb to catch up to gender not being binary. It's a legacy from their origination which was decades ago.