Edit: Protected classes is a legal term and is irrelevant to the topic here. If your argument can be used to support a statement or action that you consider incorrect or immoral then it is not a good argument. After all "Their company, their choice." has in fact been used in the past in order to discriminate against minorities.
But feel free to replace "racial minorities" with a non-protected class such as "blonde people".
Edit2: "You can choose to be vaccinated (minus the obvious medical exceptions), you can't choose your minority status."
This is again irrelevant to the topic. I am arguing against the hypocritical "their company, their choice" argument. This new argument is even worse because similarly one can say the disgusting "you can choose to bleach your skin if your company does not like black people".