ὡς δ᾽ αὕτως ψόγους νήφοντος μὲν οὐκ ἀνεκτούς,
I would expect μή here because it is generic, like in πρὸς τῷ μὴ ἀνεκτῷ that follows.
The participles νήφοντος etc that refer to the lover are said to be in G abs but why not dependent on ψόγους?
It’s a highly animated passage, and the syntax can’t always be pinned down with any exactitude. The ου/μη shift from ουκ ανεκτούς to πρὸς τῷ μὴ ἀνεκτῷ seems quite natural to me. As to the two participles, I don’t think it makes any real difference whether we read them as genitive absolute or as dependent on ψόγους. Doesn’t it amount to the same thing?