It's very unclear from just the wikipedia text what this actually was (and even then I don't give Trotsky a pass on this at all), but what happened was Germany and Austria-Hungary had seized chunks of Ukraine in Operation Faustschlag, the last offensive of WW1, and Trotsky wanted men fighting the whites in the area not the German and Austro-Hungarian occupiers in Odessa I think out of fear it would ignite a wider war as Bolshevik aligned forces in the area would be violating the Treaty of Brest-Litovsk which made peace with Germany, Austria-Hungary, and the Bolshevik government in exchange for letting Germany and Austria-Hungary keep the occupied parts of Ukraine and Belorussia until independence was established or something (not clear, the troops were out by late 1918, but the left SR uprising was in July, and the peace treaty was in early March).
It's very unclear from just the wikipedia text what this actually was (and even then I don't give Trotsky a pass on this at all), but what happened was Germany and Austria-Hungary had seized chunks of Ukraine in Operation Faustschlag, the last offensive of WW1, and Trotsky wanted men fighting the whites in the area not the German and Austro-Hungarian occupiers in Odessa I think out of fear it would ignite a wider war as Bolshevik aligned forces in the area would be violating the Treaty of Brest-Litovsk which made peace with Germany, Austria-Hungary, and the Bolshevik government in exchange for letting Germany and Austria-Hungary keep the occupied parts of Ukraine and Belorussia until independence was established or something (not clear, the troops were out by late 1918, but the left SR uprising was in July, and the peace treaty was in early March).