There is a difference between celebrating and showboating. There is a difference between celebrating and taunting.
IMO as Wyner came down the final stretch he was showboating. And the bow at the end was a taunt to the other runners and to the crowd. I thought his actions did deserve the DQ.
Celebrating is fine, but it should never be done to make other runners look bad. When El G, Bolt, KB or Hall celebrated after major victories they were not trying to make the other runners feel bad or diminish there performance. Wyner was definitely trying to do that. He was basically saying, "Look at me winning against all these jokesters!"
If he or someone else represented the US like that I would be ashamed. It reminds me of the 2004 Olympics and all that dumb showboating stuff they were doing.