Why OSCMessage constructor has broken _isValid check?

[espresso3389]

I'm using this library to manipulate DS-100.
On DS-100 spec, it allows us to send messages like /dbaudio1/matrixinput/mute/{9,10,64} or /dbaudio1/matrixinput/mute/* but they are rejected by _isValid function.

For my own project, I've forked the code and comment out the lines. But I want to know why the validation is not correct or broken.