If steel becomes more expensive in the US, all else equal, demand for it will go down. If demand for steel in the US goes down, worldwide prices for steel will go down (less demand from US creates slack in worldwide demand since US is such a big player). China will be able to buy some of that lower-priced iron/steel from source that might otherwise have sold it in the US otherwise. This directly impacts iron producers, such as the ALS investees. That's as clear as I can make it.
Now Trump might meet with a different lobbyist between now and next week and change his mind, but the news was definitely not off-topic for Altius.