Women did not show their faces in the streets. Women were not allowed to hold any social position, political position. They strictly had a family position and they held their power within the family. This kind of restricted society was what Guru Nanak came into.
He wrote, in his bani, about women. He said, 'From women kings are born'. From women the whole society maintains it's strength. He says, 'So how can you call ANY woman bad?"
Really what he was saying was that no matter how powerful or rich an emperor or king is, he can not reach into the lap of God and bring a soul down to the planet earth. And yet the most simple woman can do this. So he's saying, 'Don't call her bad who can bring life onto this planet.'