At the beginning of your trading career, you will always lose. This is the law. Whatever results you show in theory, but in practice you will lose money, learn, then lose money again, then learn from mistakes again, and after a certain period of time (this period is different for everyone), you may learn to make money.
Yeah, demo accounts trading are not going to make you become a professional and trade with steady profit. The way I understand demo accounts is that they are just there to help you know how trading works; helping you to understand the basic things. That's why you can be trading on demo and winning ,and when you finally start real trading you will start losing. That's to show the demo trading doesn't automatically make you a pro, you still need some serious lessons to be able to pass. So a demo is not enough , you still have to work hard and learn technical analysis to be able to trade well.