You're being called out, man up or shut up. Explain EXACTLY how US policy is to blame with regard to Ukraine. If your comfortable condemning US policy, then you should be just as comfortable explaining how the US is to blame in the Ukraine.
I'm not so biased to say the US hasn't cocked up things in the past and surely will in the future.
I give you Victoria Nuland from State Dept who caught deciding who should or who should not be in power in Ukraine and boasting of how much she had spent of US taxpayers $$$ in the country.