As long as they get no special consideration for their past results and are only taking something away from younger skaters IF they truly earn and deserve it then older skaters continuing past their best before date is fine. It is their life to waste. Of course there are times it becomes so pitiful it is almost unbearable to watch like Suguri, or potentially long term damaging to ones own body with almost no chance of getting the reward in return to make it worthwhile like Plushenko.
Personally I think Lysacek, Plushenko, and Weir are all stupid to come back as they have no chance of coming close to their former success, and only Plushenko might have a shot to win a medal of some kind at the Games (a very outside shot of a individual bronze or a real shot of a team medal) , but in his case he is the one who is risking long term damage to his body. However it is their lives to waste. I dont think Evan is even planning a comeback though, and it is just a big PR BS stunt like Liukin in 2010, and even then I dont think it is worthwhile as he is giving up lots of money on Stars on Ice to supposably prepare for competitions that never happen.