Even tough the color photography is available to anybody since the early 1900s [2]? Is there a reason for that? Is it a choice of art?
[1] https://www.moma.org/calendar/exhibitions/1918?locale=en
[2] https://en.wikipedia.org/wiki/Timeline_of_photography_techno...
From an artistic perspective, B/W photography absolutely has advantages from a dramatic perspective. Think of how we describe clear-cut situations as being black-and-white. In certain situations, the actual color in a scene can be extremely distracting and cut away from the photo's intended center.
Some examples from a Time piece[1]
[1] http://time.com/3803957/rare-color-photographs-from-the-tren...
1. https://www.quora.com/When-and-why-did-newspapers-start-prin...
Color cameras only became common at the end of the 60s and beginning of the 70s
Huh? What is a "color camera"?
Kodachrome film was invented in the 1930s. It wasn't immediately commonplace and, yes, we still tend to think of the 40s and 50s largely in monochrome. But color slides were certainly common by the 60s.
What was true (and what you're seeing) is that news photo reproduction for print was primarily B&W. Therefore, most news and documentary photography was still done in B&W even after color was readily available for consumers.