If high levels of home-ownership impair the efficiency of the labour market, then the costs are potentially huge. It is the job of economists to point that out.
Does home-ownership gum up labour markets? A number of papers sought to test Mr Oswald's conjecture and my takeaway is that the impact of tenure on labour markets is marginal.
[Note: as an American, I never myself would write "labour," so The Economist changed spellings to conform to their style].