Russian language was banned by Ukraine after the Maidan Massacre and anti-Russian revolution. So this is part of Ukraine strategy to move away from Russia and toward The West.

Russian language wasn’t banned. I’m a russian speaking Ukrainian. Everywhere I go I can speak russian. Legislature was changes to require workers to greet in ukrainian, yes. However, there are no restrictions on anyone speaking any language. This measure is supported by me, and most of my friends, as a way to counter-balance russification, a centuries-long process of forcing russian language in every sphere of life.

It is difficult for me to switch to Ukrainian, but I support any measure for next generation to use the language of our country.

Even if it means World War?

In a way, Ukraine might be safer than the west in case of ww3, since Russia wont want to nuke itself or nearest neighbour.