A bed is a thing, just for sleeping. It is most suitable for quiet and safety, and the door is a long-term activity, sometimes open and sometimes closed. If you go straight to the door, it is naturally unfavorable, so it is not suitable.
The main reason why the bed is facing the bedroom door is that the airflow in the outdoor activity space will affect the rest space of the bedroom and the quality of sleep. There is also the fear that the indoor air will easily be lost to the outside, causing qi stagnation and affecting health. At the same time, it is easy to lose fetal gas and not easy to get pregnant.
From our own heart, the bed is facing the door, which makes us feel insecure and lack privacy.
Of course, it's up to you whether to put it like this or not. Believe in feng shui, and you will have it. If you don't believe it, you will. Not if you can avoid it.