I am trying to make a distinction to make a point. While the journalist can also be a columnist and vice versa, I believe a journalist has to some extent bear in mind who they are working for and toe the line. While some do exercise a sense of editorial freedom to say what they want they are not totally free to express their thoughts when it goes against forces, which they cannot control.
To just quote an example to make a point, the Coca Cola Company in Sri Lanka is a major advertiser in almost all the newspapers both in Sinhala and English. When they had a strike in their bottling plant not one newspaper in the country reported the story, due to the threat by the company to pull the ads they run in the paper. So while the Sunday Leader can attack the government with impunity and exaggeration, they would not dare to cross swords with Coca Cola!
A journalist reports on areas under his or her purview and some stories are edited or excised depending on the content. He is just another employee hopefully doing a job he likes rather than doing the job just for the paycheck.
I would like to think a columnist is someone respected in their field, who can write a piece analyzing a contentious issue of the day, inevitably taking sides with less restriction on what they. The columnist hopefully rises above the journalistic constraints to write candidly about matters without fear of sanction as his stature is one that people do not want to mess about with. Some senior journalists become columnists later so they can sit in their magic chair that gives them a eureka moment each time to write a piece that is profound but understandable to the reader as is awaited with anticipation every time.
Sadly we in Sri Lanka lack good columnists who can write about an issue of the day that is debated in households across the island. Of course a good column should appear in the Sinhala press to be effective, even though the columnist may write in English, it can be translated for print. When the newspaper is convinced the column also contributes to the circulation, then the editor or owner is less likely to remove or edit the column, and so a relevant issue gets an airing however contentious or unpalatable it is to some sections of society. Newspaper publishers and editors encourage creative writing from budding columnists to add to the quality of the third estate.