Wouldn’t he have had to renounce his Finnish citizenship to be naturalised?
In any case, as he’s based in the US, the European culture of taking an entire month off a year, and of almost everyone in the same country taking time off at the same time and things shutting down for a month, wouldn’t be something he participates in. Even if he had 30 days of leave a year and took all of July off, in the US that would be a personal idiosyncracy (“that’s just Linus being Linus”) rather than a mass cultural phenomenon.