To be fair the option to select 'assertiveness' as a turn off is there for women as well but having had a quick peep it seems not many women registered on the website choose it whereas a lot of the men do. 
Can someone tell me what this means apart from the obvious? Does it just mean they are looking for someone sexually submissive and passive or does it mean that in general terms they find confident self-assured assertive women unattractive? Because if that's the case I could be single for a very long time.
Here's the link so you can see for yourself:
dating.telegraph.co.uk/s/find/search.php