Yes it is true to say that it was still frowned upon in certain sections of polite society but things were rapidly changing.
I think the answer is that a substantial proportion of men smoked and those that didn't had no strong objections to doing so. In the male-dominated society of the time it would therefore be normal for smoking to be permitted in any communal area unless specifically prohibited - exactly the opposite of the situation nowadays. Note that on the Titanic there were notices requesting passengers not to smoke in the corridors but not prohibiting them from doing so.
I did some work on the history of smoking in the UK during my career as an epidemiologist so I think I can offer a little bit of background information here.
Smoking was not considered a major health hazard until the work of Sir Richard Doll in the early 1950s, conclusively demonstrating the association of smoking and lung cancer. (Various health risks of smoking had been suggested since the 1920s but were not taken seriously.) Until that time smoking was increasing among all elements of society. The biggest increases occured during the two World Wars but, even after WWII, the trend was constantly upward and it didn't reverse for over a decade after Doll's work. In 1962 about 70% of British men and 40% of women were smokers. (That was about the peak and rates have constantly declined since.)