Cannot start Apache because port conflicts

Just installed XAMPP. Everything works fine except Apache refuse to start because port 80 and 443 used by other program. Try check which program using them, without success. Until find this post http://www.knowledgesutra.com/forums/topic/47591-skype-xampp-port-conflict/ and it fixes the problem. WTF, why Skype use these ports by default. They should uncheck by default and check only when the normal ports are blocked.