I think a lot of this is because, especially historically, people outside Czechia etc didn't know how to type Š. It's an effect of English-speaking countries defining global standards for computers, aviation and so on.
Hypothetically, and with a little exaggeration to make the point, if Sweden had somehow had that global influence in the mid-20th century, the American actress "Raquel Welch" might have been stuck with "Rakuel Velch" in her passport, and Swedish people would wonder why she was annoyed by this.
Hypothetically, and with a little exaggeration to make the point, if Sweden had somehow had that global influence in the mid-20th century, the American actress "Raquel Welch" might have been stuck with "Rakuel Velch" in her passport, and Swedish people would wonder why she was annoyed by this.