If he made a steam powered car out of bronze and wood, I can't imagine him tweeting anything that would encourage sales, but I can easily imagine a variety of things he could tweet which could discourage sales — in my imagination, this would be things like "antiques are for losers".
The premise in both cases is that a) there is at least some demand for the thing and b) customers are paying attention to him.
If a) isn't true then it isn't possible to lose sales because there aren't any. This is the "any publicity is good publicity" scenario because your baseline sales are zero. If a) is true then it's about saying things your target customers approve, and then we're back to "target customers for trucks are typically not environmentally conscious libs, and like to see them criticized."
Which was the other problem with your analogy: If he's selling some steampunk thing then he'd be criticizing whatever the opposite of that is, not its expected customers. Then the risk is alienating some other customers for some other product, but in a politically polarized environment the only way to please everybody is to say nothing. And then nobody is paying attention to you and that doesn't drive sales either.
If he made a steam powered car out of bronze and wood, I can't imagine him tweeting anything that would encourage sales, but I can easily imagine a variety of things he could tweet which could discourage sales — in my imagination, this would be things like "antiques are for losers".