I don't think omitting some of your personal life details requires any malice either. Especially with him being equally oblivious to Hikari's crush on him.Can't fault her for being dishonest. If we remove their feelings towards one another from the equation and focus soley on their friendship, Hikari was open with Yuu about everything, meanwhile Yuu was having a second life he was deliberately hiding from Hikari.
Being insensitive doesn't require any malice, only stupidity, Hikari was being insensitive because she did not know any better. Yuu was actively hiding his relationship from Hikari, which is a consicous decision to keep her in the dark, it is a malicious betrayal of trust.
But well, not much to argue here about.