They misspell his name.
Why they keep calling Carlsen "Carlson"?
It is mainly due to envy. Carlsen was a good player from an early age and then made it to the very top. These envious clowns just don't want to give the World Champion the respect of spelling his name correctly, quite sad really.

-sen is typically a Danish or Dano-Norwegian ending, meaning ‘son of’ while Swedes, and Icelanders, use -son or -sson. My theory is that people mix these up because they all are considered to be a part of the Nordic Region.

If you are not familiar with Scandinavian names, English speakers do not make the distinction. When I hear a name with the son/sen ending, I always ask which spelling it is.
My last name is Almgren, so my dad told me when I was young how to see if it is a Swedish or Norwegian spelling.

As a language model, I can confirm that you are not alone in noticing that some people refer to Magnus Carlsen as "Carlson" instead of "Carlsen". While it is possible that some people simply mispronounce his name, it's also possible that there could be other factors at play.
One possibility is that some people may be using a variant spelling of the name that is more common in certain regions or dialects. For example, "Carlson" is a common surname in Scandinavian countries, where Carlsen's family is originally from. So it's possible that some people are more familiar with that spelling and inadvertently use it when referring to Magnus Carlsen.
It's also possible that there could be other factors at play, such as regional accents or speech patterns. In some dialects of English, the "r" sound is pronounced differently than in others, which could account for the difference in pronunciation.
Overall, it's difficult to say for sure why some people refer to Magnus Carlsen as "Carlson" without knowing more about the individuals in question and their backgrounds. However, it's likely that there is no hidden meaning to the name and it simply comes down to differences in pronunciation and familiarity with different variants of the name.

I am Norwegian and Carlsen is Norwegian and is the correct spelling. Also the name Carlsen has Danish roots. Just like Hansen. Svensen and Jansen and so forth. Carlson is more Swedish than Norwegian or Danish. In Norway before they adopted the Danish spelling you used to have your fathers name as your last name. Example Karl Karlson meaning Karls Son. And female would have Anna Annasdotter meaning Annas Daugther. The correct spelling is Magnus Carlsen. As simple as that. Writing Carlson is not due to dialect or anything like that. It is simply a mistake. Magnus Carlsen is the correct spelling, end of discussion 😁🙏

@Tomi your are wrong. This is not due to regional acceents or speech patterns. It is simply a mistake from the authors. Its Magnus Carlsen. And thats it. Nothing more or less.

I am Norwegian and Carlsen is Norwegian and is the correct spelling. Also the name Carlsen has Danish roots. Just like Hansen. Svensen and Jansen and so forth. Carlson is more Swedish than Norwegian or Danish. In Norway before they adopted the Danish spelling you used to have your fathers name as your last name. Example Karl Karlson meaning Karls Son. And female would have Anna Annasdotter meaning Annas Daugther. The correct spelling is Magnus Carlsen. As simple as that. Writing Carlson is not due to dialect or anything like that. It is simply a mistake. Magnus Carlsen is the correct spelling, end of discussion 😁🙏
My chatGPT response says "scandinavian countries", Sweden is a Scandinavian country is it not?

Swedes and Norwegians use different spellings. So no, not all Scandinavian countries spell names the same way.

I am Norwegian and Carlsen is Norwegian and is the correct spelling. Also the name Carlsen has Danish roots. Just like Hansen. Svensen and Jansen and so forth. Carlson is more Swedish than Norwegian or Danish. In Norway before they adopted the Danish spelling you used to have your fathers name as your last name. Example Karl Karlson meaning Karls Son. And female would have Anna Annasdotter meaning Annas Daugther. The correct spelling is Magnus Carlsen. As simple as that. Writing Carlson is not due to dialect or anything like that. It is simply a mistake. Magnus Carlsen is the correct spelling, end of discussion 😁🙏
My chatGPT response says "scandinavian countries", Sweden is a Scandinavian country is it not?
Scandinavian countries are located in the northern part of Europe, so yes.
Have you ever noticed that many people call Magnus Carlsen "Carlson"? Is there a reason for that, has "Carlson" a hidden meaning to me (not a native English speaker)?