The parent comment topic is the benefits to US workers working on US market products. If Ford's US market footprint and manufacturing workforce has relatively shrunk over the decades, then that is absolutely relevant to the concern of long-term benefit to US workers.
Exactly. When we're talking about US auto unions, the market for those vehicles pretty much is the US market. The rest of the global sales are made with global (typically non-unionized) workers. If Ford can't make competitive cars for the US market, it doesn't speak well to the union vs. non-union competitiveness.