Elio has a near healthy balance of idealism and pragmaticism, but leans towards the former. This ties in with his generally magnanimous and brotherly persona, wanting the best for nearly everybody - especially those who he considers his "true friends".

However, he's also very observant and possesses a keen sense of self-awareness, so he knows how to approach certain situations; he knows that not everyone is genuine and people will use him for their ends cough*Lusamine*cough. If his instincts are telling him to cut ties, not befriend, or even interact with certain people, he will act on it - which will give off the impression that Elio's either cold-hearted and distant or he sees himself above others (which isn't the case). He simply doesn't want to be put in a position where he will be unnecessarily caught in trouble that's more than what he can handle.

So while Elio's trusting and can see the good in others, it's not to a fault. He knows when to let his guard down and when to keep it up, especially given specific circumstances when such decisions need to be made.