It was sad to hear the larger construction companies using their buying power to purchase all available stock and store in their warehouses with no assigned jobs. They were pushing smaller construction companies to the wall when they couldn't access any stock for jobs they actually had on.
If you are a construction company and anticipate a possible/likely disruption in one of your critical raw materials and have the funds to protect your business, what else would you do? It doesn’t sound predatory; rather it sounds eminently sensible.