Yup. I am concerned, because it sounds like a lack of mentoring on a technical and an organizational level. I've made similar mistakes and I dislike it, but my lesson is: a junior should have mentors they can lean upon and draw into meetings for technical and political support. Or lean upon just whenever. It can grow overbearing if the junior doesn't grow wings, but under-mentoring and seeming abandonment inside the org can be much, much worse.

Like, why are they complaining about this on hacker news? They should be venting to their manager (we can see why that fails), or some engineer with some clout they trust. If they don't have these avenues, that can turn sour quickly.