Well, for one, Sonic has no way to kill Ike at all safely, as any possible kill he can make would be entirely due to player error. Ike however, can much more easily kill Sonic due to how necessary it is for Sonic to get inside. His ways of getting in, though, while there are mixups, will eventually be read at top levels, so yeah.
Also, if Inui thinks Ike is so garbage, why are you beating it? Why is Inui using the 5th worst character in low tiers, when there are obviously 10+ better characters to use? Something's wrong here...
Is it possible that Inui really likes Ike, but he's simply putting him down to keep him in low tiers so he can keep winning? If he loses, it's obviously because he's using the 5th worst character, and if he wins, it's obviously because he's the better player. He has ultimate john material right there regardless of winning or losing.