Don't be mad just yet. First of all, I have to say I don't hate Coria. I don't even "dislike" him despite all his whinings on court. I just think he's different.
One thing you have to accept is that people can interpret things in so many ways. And it's no one's fault if they do not come out with the same message as you do. Tome, and again I have to say that TO ME only, the reason Coria's statement seems like an excuse to many people is because it's taken out from the context that he constantly tried to get off court at the end of the first set. Sure, we would never know what was actually in his head at the moment. But we couldn't help but wonder whether he would wanna get off the court if he was in the lead. I am not attacking Coria in particular here, but about players in general. Who would wanna get off court and reset the momentum if they are in the lead? That's why when he commented about the court condition again in the press con, it came off like an excuse.
As for your quoted comment from Nadal, I think he has solid, objective proof to back that up since every replay shows that the ball was out. However, he didn't linger long arguing for that point (which, as much as I love Marat, I think Marat would
) and just kept playing. I heard Coria complains about the line calls for so many times...but sometimes he's right and I don't think he's making excuses then. You may read it in that way if you like. But to me, these are two very different cases. One is very subjective and felt only by a player, while the other is pretty much scientific, objective and can have many eyewitnesses. So they are pretty incomparable here.
I can give u some examples. Complaining (rightly) about bad calls is one thing, if everybody sees that the call was bad, I think most people will sympathize...as long as the players don't blame it all on that particular call. Classic examples...Serena VS Capriati in USO2004...who can say Serena was making excuses when she complained about the calls?
On the other hand, excuses are some factors players shouldn't let that to be the case or to get better of them, i.e. court conditions, bad balls, winds, heat etc. Yep, top players can lose becuz of heat, but they shouldn't cite that as reasons why they lost. For example, I love Marat...but he's a master of excuses. It's always bad courts, bad balls, too windy, bad atmosphere, not enough light, etc. etc. (though he usually does it in an adorable, humourous way which spares him from MTF butchering) THOSE are still excuses.
At the end of the day, if you are Coria's fan. It really doesn't matter what everybody else says. If you don't think he's making an excuse, that's fine. I think Roger's fans have far worse problem when people said he is arrogant.