The real reason is to contain China at any cost and US is accusing Russia of violation of the treaty is just a pretext.

So, while many news outlets have thus far focused on the Russian dimension of America’s withdrawal from the INF Treaty, and the potential challenges for Europe, don’t be fooled—the real game to watch is being played in Asia.

http://www.yahoo.com/news/why-america-leaving-inf-treaty-173200541.html