gibbs thought enough of him to move up in the draft,
Gibbs screwd up. He moved up for D'Qwell Jackson, then Jackson was taken the pick before him. That's why Washington was so confused about what to do and had to take so long to decide what player to pick there. The trade for Washington to move up was announced at the same time that the Jackson pick was announced.When you move up for a player, you walk straight out and pick him.
This is all speculation. What seems more likely is that they were reaching the point of drop-off to the next tier of talent at OLB, a position of need for the 'Skins, and they determined that they needed to make sure that they'd get a guy there who they could develop and play this year. It's possible that they wanted Jackson over McIntosh, but it's certainly not definite. McIntosh was the only one of the two with a private workout, and he's also known as a highly intelligent player (he had the best test score out of all of the LB's IIRC), something that Gregg Williams values. Gibbs and the staff have also publicly praised the quality of the Miami program where McIntosh comes from.
Either way, McIntosh seems like a solid pick given their need, and a good fit for their system.