In a pure sense you are right, however, state-subsidized materials being “dumped” in the US market below market prices to eliminate domestic producers, also raises prices when the purpose of the dumping achieves its goals.
There's really no such thing as "dumping" in the market. The supply and demand of marketplace is transacted by the voluntary cooperation between buyers and sellers in their own self interest. Buyers freely choose the best product for the best price and will generally will not buy low quality junk because that generally is not in their best interest.
How does that process "raise prices"?