Latex is sticky, but you should be able to turn the moulds. It is impossible to know the exact reason for your problem. Maybe the mould isn't thick enough to keep its shape and so the inside surfaces get in touch too easily. Or maybe the latex isn't dry enough when you try to remove the moulds.
If you're going to use the mould for plaster casting, you can apply powder also to the inside before turning the mould and that will fix the problem. If you want to do resin casting, you can't use powder as it will show on the casting's surface. You just need to be careful when removing the moulds. And always remember that if it looks easy on the video, it's because I've been doing this for 15 years, so I've had a lot of practice.