I completely agree - that old Treaty is long since obsolete - but it is a record of claims which are still valid in the eyes of some nations in the Middle East - especially Turkey.
Turkey sees itself as the protector of the Tatar people of the Crimea. They, in turn, are Muslim and anti-Russian. Many of them managed to return to the homeland after decades of exile, as described in that article, and they are now a growing Crimean minority.
Turkey tries to talk about Turkic brotherhood (Turkic nations include Uighuristan/Xinjiang/East Turkestan, Kirghizia, Kazakhstan, Uzbekistan, Turkmenistan, Turkey and Azerbaijan), but is powerless against the Chinese atrocities in Xinjiang, far less in Russia. The Turks have other things to worry about