I think I only set baths up to wash away cum, not pubic hairs. Thanks for pointing that out!
When you say it doesn't count, what do you mean? Currently there is no impregnation mechanic, that is just preparation for it.
Part of the reason it is hard to drag down her purity is that not all features of the game exist yet. If it was too easy then once those features are added, Blitzalla would crumble immediately and then why bother having purity at all?