Because there is logic to why you wish to be with her, so there must be a reason why one would be embarrassed about it.

[as far as literature and the like goes, love is often portrayed as something incomprehensible and beyond definition -- and that certainly is true of the feeling itself, he thinks. after having met shinji, he doesn't think he could ever find words that would properly describe how he feels for him.

but the why is an entirely different matter. people knew what they liked about others, and even if a feeling itself was too complicated to explain, the reasons behind it shouldn't be.]