I would love to know why exactly Kei is a bad matchup for Ferrer. What matchup advantage have you identified in their past matches? Kei has beaten him in USO and Olympics because he's a more talented player, that's all.
And also, how exactly is a close 5 set defeat at USO and close three set defeat at Olympic 'humiliating defeats'?
I love how you try to build a rational argument with your own biased opinions as a basis. Of course, in your dreamworld, Nishikori is a better player than Ferrer so nothing of what I'm going to say makes sense. But in the real world, Ferrer is world n°5 and Nishikori is n°15.
Why do I say Nishikori is a bad match-up for Ferrer? Well, simply because he has beaten him 2 times out of 3, in spite of being ranked far lower.
And why humiliating defeats? Well, because even though Nishikori had already been doing well before that, his victory against Ferrer in 2008 in the US Open was quite a surprise and it was deemed a counter-performance for Ferrer (whether they were right or wrong, people certainly made fun of him for losing to Nishikori - and based on rankings alone, they were right since Ferrer was n°4 Nishikori was ranked only 63 by the end of his great 2008 season).
Actually it certainly was a big counter-performance from Ferrer, it was also one of his most embarrassing moments (the bitching against the umpire thing), AND the beginning of his big slump that left him with no titles at all in 2009.
The loss at the Olympics was also a big surprise, and a great disappointment both for Ferrer and his fans. The Olympics meant a lot to him, and with Nadal injured, he was the best hope for Spain, many people expected him to get a medal. So, this one was maybe not humiliating, but it was certainly quite unexpected and quite difficult to swallow.
So, yes, for a Ferrer fan, Nishikori would certainly be associated with very bad memories, although not as bad as Gael Monfils.