That's a rather uncivil comment. You're replying to a commenter who's a self-proclaimed Russian patriot and nationalist. There's no need to go shouting about motiviations when they've already been laid on the table.
I don't believe it's a rude comment at all, given that:
1. Russia and Ukraine were the same country until 1991. The culture was exactly the same until that time. Until less than half a decade ago, Ukraine was led by a Russian puppet. Believing the culture is "different" is blatantly ignorant or deceitful, and it's unlikely the poster is the former.
2. Russia is stressing the difference between itself in Ukraine to rouse support for its take over of Crimea.
I moved from Russia in 2012, and would gladly move to Ukraine, if not for that movement away from the Russian language.