it's only fair if their language rights are systematically are discriminated against and the judicial system has been unable to curtail this phenomenon, which is not the case
the constitution of Ukraine is fait accompli, you can call it unfair, so was the decision of Ukrainian citizens including Russian speaking ones
for many proponents of the second language it's simply an excuse to not learn and know Ukrainian
moreover this law opens the whole can of worms for social stability in the country and is dangerous for its very integrity
here's a very sane article on the topic of Russian in former soviet republics