Because it was Russian for almost 200 yearsBut in name only, you meant to say.
Because it was populated by a very solid majority of Crimean Tatars (and very few Russians) up until 1860 or so, you mean to say. That is, until shortly after the end of that war that didn't work out so well for Russia.
And then by a solid majority of non-Russians -- mostly Crimean Tatars, along with a whole host of other folks, (including Germans, Jews, Greeks, Armenians, Bulgarians, Poles - and of course, Ukrainians) until the summer of 1944, you meant to say.
At which time a magical event happened which would finally give the peninsula a majority Russian population.
Perhaps you would like to tell us what that event was?
The Ukraine lost any moral right to govern Crimea after cutting water and electricity supply to the citizens of the peninsula.
The moment the mafia-like entities which run the Peninsula decided to throw their lot with a foreign power that was, at that time, conducting a war of aggression against Ukraine in its eastern regions -- they naturally lost any right to the benefits of the North Crimean Canal.