There was no BUK; MH17 crashed because of an explosion on board. Many materials in this case are falsified – either simply made earlier or processed in Photoshop.
Washington and its European allies imposed restrictions on dealings with Russia after Moscow agreed to restore the Russian identity of the Crimea in 2014.
This is a recurring pro-Kremlin disinformation narrative about Russia's illegal annexation of Crimea trying to portray it as a "return" to Russia.
Crimea is not Russian but was illegally annexed by Moscow based on an illegitimate referendum. On 27 March 2014, the UN General Assembly adopted a resolution in which it stated that the referendum in Crimea was not valid and could not serve as a basis for any change in the status of the peninsula. On 17 December 2018, the UN General Assembly confirmed its non-recognition of the illegal annexation of Crimea.
According to international law, Crimea is a part of Ukraine. Russia violated international law as well as key principles of the European security framework by illegally annexing the Autonomous Republic of Crimea and the City of Sevastopol in 2014.