I caught the orange man talking on the radio, as I am not american I knew it was going to be something stupid but this? I thought it was a joke, an onion like thing, but nooooo. What sealed it is when in the very speech about the new 100x battleships, trump stated that he did not know why the us stopped using battleships....
However:
2. As mentioned in the video, they are very power hungry. Like they need their own nuclear reactor in a ship to power it.
3. The barrels only last less than a dozen shots. This means you either need tons of extra barrels and the crane to replace them, or you need a logistics ship to do that every few hours in a battle.
In short: railguns are neat but we don't have the tech to power or build them.