Van Gaal, 71, is one of the game's most outspoken characters and has previously criticised the decision to award Qatar the tournament and said he supports Dutch fans boycotting the finals.
The Netherlands, who begin their World Cup campaign against Senegal on Monday, were the driving force behind a decision from a number of European countries to wear a rainbow-coloured 'OneLove' armband during the tournament in a message of anti-discrimination, and in defiance of FIFA - who have proposed their own armband with a series of its own slogans.
France, who were initially among eight countries to join the OneLove campaign, have since decided against defying the world governing body but the English and Welsh FAs have signalled their intentions to stick to the plan and accept a fine from FIFA if necessary.
Asked if the Netherlands were sticking by the OneLove armband, Van Gaal said: "I am no longer going to speak about political issues, I'm speaking about this coming match and I put a full stop on all these issues.
"After I invited the migrants to watch a practice session, I requested all our players to put a full stop on that and focus on the match against Senegal."
Like England and the USA, the Netherlands offered a group of migrant workers the chance to watch training in an event organised by FIFA.
The Netherlands are in a group with hosts Qatar, Senegal and Ecuador -- and could meet England in the last 16 if one side finishes runners-up and the other wins their group.
Van Gaal believes his squad have the quality to be world champions and believes tomorrow's opponents are their biggest rivals in Group A.
"I believe in this group of players," said the former Manchester United coach. "In 2014 we came third with a squad of lesser quality and with this group I expect more.
"I think that we could become world champions but there are squads who in my view are at a higher level to my squad. It's about how the squad deals with that. We can become world champions, whether we will become world champions is a second issue. But we can.
"Qatar I believe has been working on preparation for the World Cup for six months and there's a lot you can do in six months. I've been working for not even a week, so there's a big different there.
"Senegal is Africa Cup of Nations champions which isn't nothing. They defeated Egypt [in the final] which is an important country with big players.
"At first glance I think Senegal will be the toughest opponent. Them and Qatar I know about but Ecuador for me is a mystery. For a long time the question was whether they would participate, my scouts have analysed them but I have yet to do that. But I think Senegal is stronger than Qatar."