It also seems to me a good argument not to race in Sochi. I think it's for two reasons, a sort of boycott by him against what Putin is doing with Russia right now, but also because it could just be very dangerous there. The situation with Russia can escalate quite quickly and in principle you are not safe anywhere in Russia. F1 is wise to remove Sochi from the calendar for safety reasons.
This is what I think as well, while some people may decide to not race out of principle I think the main reason would be the security of the pilots, their crews and the public in general, after all if Ukraine is annexed by Russia then it is obvious there are going to be freedom fighters that will not accept this and they may try to damage the current government by attacking civilians, and a public event like this could be a target for them, so it is better to avoid racing there for the time being.