Eh, I don't think that's really a big deal.Wherever he can claim a slight advantage (even if it turns out to be 51:49) is important for his image. If everyone thinks that sonic really doesn't have the edge over every character that commonly appears in tourny's, then we will start to see less Sonics being played.
It's really a matter of learning how to play the matchup moreso than the matchup ratios. The people who use ratios to choose a character are people who are looking for counterpicks or people who don't actually main the character.
I don't really imagine many people choosing to secondary Sonic or using him as a counterpick because there are better characters to CP with out there - however, people that use him have reasons like fun, fanboyism, or playstyle compatibility that affect their choice much more than any matchup ratio could.
TL;DR
The Sonics that place/matter don't really need MU ratios to decide whether or not they play as Sonic. lol.