I would assume the author of that comment was using "grey" to describe an opinion that is more nuanced and carefully considered. A black/white opinion would be

I would assume the author of that comment was using "grey" to describe an opinion that is more nuanced and carefully considered. A black/white opinion would be hyperbolic or simply expressed to provoke reaction. So if that's what a grey opinion is... then yeah. That's more valid. Especially if you value conversations aimed at exploring some reality rather than performative shouting matches.