Seahawks Fan

Gabe and I had an interesting conversation this morning. Des had taken the boys into Idaho Falls yesterday to do some school shopping, and Gabe was giving me the lowdown on the stores they visited, and the items they bought. He mentioned that they stopped inside the sports store to look at "Niner-gear". He also mentioned that there was a guy wearing a Seattle Seahawks jersey. This is how the conversation went:

Gabe: "There was a guy wearing a Seattle jersey in there."
Me: "Oh yeah? Did you tell him he needed his butt kicked?"
Gabe: "I think he already did."
Me: "Why do you say that?"
Gabe: "Because he was in one of those chairs." (At this point he makes a strange motion with his arms)
Me: "What chair? A wheelchair?!"
Gabe: "Yes, one of those."

I don't think he understood, nor still understands, why that is so funny to me.