considering that TC employees regularly check news.yc it's plausible to assume they automatically upvote all TC stories.
As far as excluding TC content goes, while I could live without it, think about the number of AWESOME discussions that would have killed in the past, then ask yourself if that's what you want for the future.
ValleyWag posted a flurry of articles which were counter to YCombinator interests and now ValleyWag articles are automatically posted with the dead attribute. The same scenario could happen with TechCrunch.