There's a thread on this already in relation to pool.
It's not about physical strength it's about access to the sport for women across the board, sponsorship at the higher levels, men's and women's bodies are different in terms of muscle twitch, hand eye co-ordination.
Show me a female darts player who hasn't been hassled down the pub because the men want to play or hasn't been able to put in the same practice hours because of childcare or not feeling able to go into male dominated spaces and take up space in them in the same way men do. Etc etc etc
And maybe women just want to play other women. Maybe it's as simple as that.