What do you think EB visas are: immigrant visas or work visas? Answer: they are both.

You're correct. I spoke a little too loosely, there are many different kinds of visas, but something like 95% of all work visas issued each year fall into the category of non-immigrant.

I'll concede that this statistic is cold comfort if you fall into that 5% category, but the point is that work visa almost always means non-immigrant.