Golf requires large fields, so it is very expensive, so only wealthy people can afford it, so this is why it became a game for the wealthy.
Other than that, it does require physical skill, if not, all the players would have about the same score.
Other than that, it is less physically demanding, so it's good for older people, and people often grow old before they manage to amass wealth, so yet another reason why is it popular among the wealthy.
For those who were wondering: https://en.wikipedia.org/wiki/Baring_family
Now that I looked through them, they are reporting on the Asia Times article. It's written by Stephen Bryen FWIF.
There are multiple sources in Russian: https://yandex.ru/search/?text=France+foreign+legion+in+ukraine
$100 is 1/6 of median salary in Russia. An average person can't afford golf.
And yes, skiing and buggy racing are also considered rich people sports.