Sharing on public postings in Google+ is crossposting?

Sharing on public postings in Google+ has sometimes the same bad  effects as crossposting to many newsgroups on different servernodes in good old usenet.

Question: Might it be better to link to other public postings instead of sharing it?

Animated gif below illustrates a real sharing usecase:
 wrotes the first start posting, after some discussion  reshared it. than I wrote a followup to Serafinas reshared posting and somebody other rereshared Serafinas reshared posting.

Url to the real sharing usecase:
https://plus.google.com/u/0/107864812147929920439/posts/cYVhC4bjcYb