Suspicious of what? None of those got any comments. Sometimes stories slip off the radar before being noticed, the first time, or first several times. And HN even posts 'dupes' themselves sometimes, to give undercommented stories another go. see https://news.ycombinator.com/item?id=11662380
I submitted a blog post the other day that got 150 comments - I only noticed afterwards it had already been submitted 6 or 7 times before in the months preceding, each without attracting any comments.
No need to be suspicious. AFAIK, HN encourages folks to reshare if they think that a quality post slipped off without much engagement. I even got an email from someone at HN encouraging me to reshare my couple of years' old post again to see if it sticks this time around.