Hi Israa, I'm sorry that you didn't feel the room was private enough. I did get the sense that you were uncomfortable staying here. I've never had this feeling or feedback before from any other guests, so I wonder if your privacy need are greater or more specific than usual.
Staying in an Air bnb in a room, rather than renting the whole house means that you will be a part of a household for a few days, this involves talking to people, asking questions (for instance using the hairdryer at any hour would have been totally fine! ) and opening the door if people knock or need to talk to you, (but not while you're changing of course!) as I did a couple of times, and felt I made you uncomfortable by doing so. I did get the sense that you wanted not to be spoken to or bothered which, I'll be honest was uncomfortable for me. I am most happy to leave guests to their own devices but do expect the door to be opened if there's information I need to pass on. It's a courtesy.
There is no curtain on the door because the front room lights the hallway. Also, I'm not comfortable having internal locks on the bedroom doors, this is for fire safety reasons, but also because that's not the kind of house this is. If you need to be behind a locked door to feel safe, perhaps hotels are better, as you can't guarantee that with Air bnb. You're in someone's house and need to be prepared for that.
I hope that you still enjoyed your stay in London, and thankyou for giving this feedback privately. I wish you safe and happy further travels.