Yeah that is true, but I also did not claim that. Anyway I have a hard time finding any celebrity in office in the countries I lived in (Poland, Germany, Sweden, South Korea), doesn’t mean it doesn’t happen though, just that it looks to happen much less often.
I had a look at the list you linked and was surprised to see the list pointing out Germans and Polish people so I looked a bit dealer.
The German guy was in the left party which is so small that they always have trouble to get over the 5℅ necessary to be in the Bundestag, so he has never been in any leading position. And even the nomination to become president failed. And even if he became a president, in Germany that is not a leading position, a president just represents a country like a King.
In Poland, for Lech Kaczyński (who was the president of Poland) the wikipedia article down not even mention his work as an actor. On IMDB 4 entries are there. He was voice acting for a animated movie as a 13 years old and this is the biggest of the movies he was involved. The next next is a documentary, so he is not acting. The next one is a special episode of a game show to which politicians have been invited as participants. So no acting here either.
The next from Poland Jarosław Kaczyński, the twin brother also only had the voice acting as a 13 years old and documentaries where he didn’t act listed on his IMDB page.
The third and last polish guy in the lis fits the description of a celebrity and politician in power, he was elected into parlament.
For Sweden nobody is listed. Same for South Korea. So from the countries I lived in my feeling that this doesn’t happen is supported by the list you linked.
But other Asian countries, god damn! The lists for India, the Philippines and so on are soooo long! I didn’t expect it. So it’s really different in different countries.