That is not true.

There is a process, it's usually tedious but it exists. I did it for Singapore, the US and Israel. They mostly took multiple months but I never wanted to take any chances. For the US it was a "B-1 in lieu of H-1B" visa for example.

Attending a conference is something different than what these workers did. There are rules around what a "business trip" is and what is not and what "work" is.