e.g: " they either are set to dead for some reason "
For the one example I looked at (from the links you provided) PG explained that the reason it was set to dead was that it was a duplicate. http://news.ycombinator.com/item?id=746980. That isn't "some reason". That is a very clear reason.
"YC community felt either threatened or uninterested"
The first guess is stupid.
What basis do you have for this? Just state the facts ("These didn't get many upvotes") and leave the amateur psychoanalysis where it belongs.
Imagining conspiracy theories where there aren't any is worth a downvote.
As sachinag points out above, if the community didn't up vote the submission, it didn't upvote the submission. That's all.
Now if something you submitted didn't get any upvotes there is no need to whine about it or imagine a conspiracy. It happens to all of us.