Why are the minifigures so fragile?

The question in the header is a valid one, but I suppose this post is also partially a vent about minifigures overall? The other day, Sora's arm broke when I was putting a blade in her hand. Same thing happened to my Imperium Ras arms (both of them, tragically), and Climber Zane. The Zane situation wasn't as bad, because I had a spare minifigure with same kind of arm color as him. Ras and Sora on the other hand both feature unique side arm printing, so I can't just find a replacement in my...