I find it hard to believe the tea flinging incident or the swearing. However if it is true, it would suggest M has serious issues .
Just Facetimed with a friend in Toronto. He's a photographer who used to do a lot of fashion shoots. I mentioned MM, asked if he'd worked with her. He hadn't, but is friends with an award winning and well respected director/photographer who worked with MM on Reitmans' advertising campaign. Reitmans is a low end women's clothing store, and MM had a line of clothing with them, and did some ads/promos. The guy said that MM was absolutely horrible, the worst person he has ever met, just mean to the bone.
My friend had specific stories, and based on those, the tea flinging incident is not unbelievable. I'm not saying it happened, just that based on what I heard, it's not outside the realm of possibility.