I do not want to create controversy, just to know why there are so many foods (water, butter, bread...) and in different brands, even international (Nestlé..) who sell their products with halal certification

What are the advantages of selling products in a country that only has 5% of the population who are Muslims?

Please be polite and courteous in your replies 

 

The products are often generically labeled to be sold all over the world, they are not specifically catering to 5% of the Thai population.

Even 5% represents a couple of million people and and worth marketing to. A percentage of 40 million tourists each year would also be Muslim.  Nowadays products will also have 2-3 languages printed on the back, no matter what the percentage of people speak that language.

 

Only a percentage of the population are diabetic but products are labeled low sugar etc.

Even so some people who do not like to have pork or pork fat ingredients in their diet as well as the manner of how animals are being slaughtered and prepared for consumption, finds halla food to suits their eating prefencess...

It's one way that Muslims can get kafirs to pay for jihad.  Halal certification isn't free.  Selling halal-certified food to non-Muslims simply raises more money for to support Islamist objectives.