Of course, because we're used to bullish and bearish, right? 
So the color red is for Down and green is for Up. I agree with you, but as long as the gamblers pay attention to the numbers, then they won't be distracted by the colors.
It is popular color used on exchanges and the casino can consider of changing their colors to more common colors. They also can consider of adding new color sets including Green /Red set and allow their customers to customize colors if they want. So the color red is for Down and green is for Up. I agree with you, but as long as the gamblers pay attention to the numbers, then they won't be distracted by the colors.Besides a default color set which can be the current one or Green/ Red set, users are free to choose color in profile settings.
It is my another idea and proposal for the company to make improvement of their casino in order to serve their customers better.