The heading of the letter to the Sun, March 11, "Socialism assumes a benevolent leader," is a correct statement. Unfortunately, the writer goes on to describe not socialism as practiced by modern western countries, but communism as it was practiced by the old Soviet bloc and still is by countries like Venezuela.
The World Happiness Report (weforum.org) is an annual publication of the United Nations Sustainable Development Solutions Network. If we consult the March 2018 report, we find the six countries in which the people are happiest are Finland, Norway, Denmark, Iceland, Switzerland and the Netherlands.
The above six countries may all be considered to be socialist.
To quote from the report:
Nordic countries take four out of the top five spots and are well-known to be stable, safe and socially progressive. There is little corruption and the police and politicians are trusted.
Money cannot buy happiness; some of world’s richest nations, including Japan and the U.S. (ranked 18th), are found much further down the list.
The report is based on international surveys in which thousands of respondents were asked to say where they felt they stood on six significant factors: GDP per capita, social support, life expectancy, freedom to make life choices, generosity and corruption levels.
The details may be found by googling World Happiness Report 2018.