Less Wrong isn't obviously a bastion of left-wing ideas, so it's possible whatever is filtering out conservatives from posting here is also filtering them out of academia.

When I started posting on LW, I was - depending on your terminology - very conservative. If there are any barriers that prevent conservatives from joining, then they didn't affect me. (Edit: this is anecdotal; I might just be an outlier.)

I should point out that my views have drastically changed since joining. Though I try to avoid aligning with any particular political group, libertarian-progressive might be accurate. I'm interested in seeing where other people in the community stand after the next census.