Did Kroger / Kevin Kline say what he said for a reason? / Spoiler

I like that explanation.

My initial impression was that, having feelings for her, he was uncomfortable that she was prepared to move on to new horizons and, perhaps unconsciously, wanted to take her down a notch. Or that he had bought into her idea of herself as "just a maid", and that only when this idea was mirrored back to her did it stir up indignation.

Okay, that's understandable and I totally agreed. But, why did he have to be such a jerk in the beginning, before they played chess? I know that his character supposed to be a grumpy and somewhat strange social-outcast-middle-aged-widower; but, why all the uncivilized and condescended attitude toward her when she was "just" his cleaning lady? Even if he was in grief (of the lost of his wife), he still shouldn't mistreat his domestic helper in such undignified manner/tone of voice, especially, when he was the educated one who supposed to be with higher moral ground and social etiquette. I find that his behavior was abhorrent and unnecessary for the character, especially when her character was just the complete opposite. Therefore, it's completely unbelievable and hard to swallow when his behavior just instantly changed 180 degree when she offered to clean for free in exchange for chess lessons. It's just unconvincing and very fake to watch such a improbable character development.