It's deliberate misinformation.Seemed like a fair interpretation of what was said.
First, why ask that question at all? To generate click-bait crap. If he says "yes, we intend to vaccinate undocumented workers", they post a headline and make a big deal out of it. If he says "no, we're not vaccinating undocumented workers", they still post a headline and make a big deal out of it. He chose path C, deny the premise of the question, and they still pretend he answered their question in a way to make headlines.
Second, if he's asked "will you be vaccinating undocumented workers at these plants" and his response is essentially "we're operating under the assumption that there are no undocumented workers at these plants", the obvious implication is they plan to vaccinate everyone, otherwise the answer doesn't make sense. if the answer was meant to mean "we're going to screen out non-citizens from this program", why would you bring up that they're shouldn't be any non-citizens in the plants? How does one take "there shouldn't be any, so we don't expect to" and amend "therefore we're going to use our resources to screen out the people we don't expect to be there" to it? That's a silly thing.
The real tragedy will be if the artificial controversy scares people away from vaccination. For clicks.