Anyone making that claim would have to have read those sermons. Give us an example of a sermon Calvin wrote on the beatitudes which you've read.
An excerpt from Calvin's Sermon on Meekness particularly reminds me of you:
"Everyone around us follows his own interests and looks to his own advantage; everyone wants to lord it over others. Hence our pride, our surliness, our venom the instant we are provoked. Harshness and even cruelty abound. We are vindictive and cause no end of trouble: it is as if lightning should fall from heaven every time someone is offended. So if in the course of life we endure many difficulties, we do not have to look far for the explanation: the pain men suffer comes from their fellow men. It is, of course, true that people all have their excuses."