The problem with robots used for practice is that humans have far more complex control loops embedded in them. Self regulation in almost all parts of their body, brain and mind. And also in social interactions this complexity comes to play.
In central and eastern europe, there is a tradition of dance lessons for teenagers, who go there to learn how to dance and behave on formal events, and to learn the basics of etiquette.
The point is, even the complete asocial self hating depressed loser will be forced to function socially in this setting, even if it is the most nerve wrecking experience.
Plus even though some teenage girls can be quite cruel, there are those, who mostly feel invisible, who are quite forgiving and kind.
Look at it from this point of view, and since you already discuss this, you have such affliction yourself. When one cannot imagine why would any girl want to even have a conversation with him, what sense is there to ponder what is going on with sex.
If you were a Soviet hikikomori, you would be shipped to dance lessons for adults. And a line of work that would force you to interact with other people and see that your fears are baseless.
If you want to learn how to be among people, you have to learn among people. Also it is the easiest way. And learning that people are generally far more forgiving than one's sick paranoid and depressed mind would thing, I don't have to spell the rest out.