It would have actually been better if Plushenko hadn't competed at all in Euros and taken care of his health, instead of presenting a watered down SP while injured. You say he wouldn't have competed if he were unprepared/not healthy... well, clearly he was unprepared if he didn't come with a quad (against Fernandez/Amodio/Brezina/Joubert), and clearly he was not healthy enough if his SP fall was actually attributed to injury. If he didn't compete in the FS due to injury from the SP fall, I can accept that... but what I am skeptical of is people defending his poor SP performance primarily due to injury affecting his ability.
Skaters have to perform while injured all the time -- but you would have to imagine that a skater only skates with an injury if they believe they can perform well, particularly a perfectionist like Plushenko. And with perfect 3A and 3Z-3T in practices leading up to the SP, I wouldn't attribute his poor performance solely due to injury - as inconceivable as it might be, maybe he actually legitimately made errors. All I'm saying is that people shouldn't rule that out and immediately say it was because of injury. Stating that you have a performance-affecting injury but are going to compete anyways is setting people up to applaud you if you skate well "he skated well in spite of injury" or defend you if you skate poorly "he skated poorly due to injury".