The Houthi now compose about one-third of the population of Yemen. They are well equipped, highly motivated, but not very well organized or trained. They are very intimidating. The Houthi are not about to go away.
Imagine the impact of a million Muslims all told, marching in New York, London, Paris, and Jerusalem to condemn all violence in the name of Islam. Imagine the statement it would make to whose who seek to hijack Islam and turn it violent.