While the Daily Mail and Russia of today are vile places, Russia isn't the Germany of 1936, although one definitely can see parallels in the steady pace of authoritarianism that tightens and encroaches, year by year. Yet, Russia is not engaging in relentless adventurism risking world war, nor is it creating deathcamps.
Civil rights today in Russia is deeply disturbing and will probably get worse before they get better. However, bad as they are, they are better than they were in 1980... when the Olympics were last held in Russia [which, uh, the USA did boycott, but not because of civil rights].
In short, boycotting isn't useful or appropriate, in this case.