why do photographers still take black and white photos?

Black and white snapshots get rid of any distraction of coloration and assist the viewer's core of interest on exceptional factors of the photo, such as the subject, the textures, shapes and patterns, and the composition. So, you can use all the equal composition techniques like the rule of thirds that you would use in color photography.

Some shoot in black and white only , not a lot  but they're out there .

   I sometimes edit a color shot into black and white .

Try it yourself . Some photos actually look better in black and white .

Sometimes, less is more.

BW is clear, cultivated and just simple!

Because they can!

Why shouldn’t they?  Black and white photography is a whole artistic universe unto itself .  

Photography is a visual language, and as with any language there are many ways of expressing a narrative.  Sometimes a narrative warrants a very flowery text, and sometimes it demands to be curt and to the point.  Well, the same can be said about expressing one's photographic vision.  Sometimes color can be the reason for the photograph.  However, often when the photo is about the shapes and textures or about the actions of those in the scene, the color can actually be a distraction in effect competing with the important elements for the viewer's attention.  For this reason photojournalists like Sebastião Salgado exclusively shot B&W.

Photographers who do do so because they are interested in exploring noir and the use of positive and negative space, which a monochromatic medium like black and white provides. 

Also, amateur photographers often lean towards black and white because, one, learning photography using black and white first is far easier, black and white being sort of like the training wheels for photography, and, two, equipping a dark room and developing photos oneself, which gives a photographer a significant amount of control over how the final photograph comes out, is much cheaper and is much easier for black and white film than for color. One can equip a dark room for black and white pictures for under $1,000, but one will spend thousands and thousands of dollars to equip a dark room for color photograph development. Then once, an amateur has gotten the hang of black and white, sometimes they never graduate to color because they simply like the medium better, what with how it simplifies images and removes attention from the subject itself and shifts it to light and dark and the interplay of light in light and dark juxtaposing space.

Think of black and white photography as the photographers version of impressionism. In impressionism, the subject isn't the objects being painted but the light that plays on those objects. That's why impressionist painters veered from realism. Realism brings focus onto the objects being painted. By sort of muddling the objects by painting them vaguely or hazy, giving just enough shape and detail to give an impression of what the object is, impressionists were able to shift focus from the objects to how the light shone on those objects, light being impressionists true subject. Black and white film works similarly because by not having the objects appear in them appear realistically exactly as they are but instead monochromatically in a way that nobody ever actually sees those objects, the photographer is able to make the object being photographed merely incidental, an impression of the object instead of an exact rendering, thus shifting focus to a subject that the photographer is really trying to capture-- light. The idea is that light as a subject is every bit as powerful and often more powerful than the object being photographed, the lighting being able to evoke a specific emotional feeling that the object itself would not otherwise evoke, but that can more easily get lost when the photograph is instead in color.