You may have a valid point but since a common theme seems to be that newer posters do not feel welcomed or that their input is appreciated I believe people are making an effort to be more generous with up-votes in this thread. I've generally been quite parsimonious with up-votes and comments here and in the welcome thread have made me feel that I should bias myself more in favour of up-votes over down-votes.

Since this is a thread about how and why females are underrepresented on LW their input is particularly relevant and so higher karma scores do not necessarily imply any further bias. In conjunction with a hypothesized general realization that more up-voting, particularly of new commenters, would be of benefit to the community I think it's possible to explain the high comment karma without postulating further bias.

I'd be interested to know what you think the unstated assumptions are though.