Software Center will not start from icon and https://askubuntu.com/questions/784695/ubuntu-store-wont-launch shouldn't have been downvoted. It this more of the malicious up-down voting?
As for the first link I can explain you why it got a down-vote, you will get the clue to when you look at this posts edit history. At the time I edited it first it was already down-voted, and my guess is because the question was a mess to read, totally without formatting.
Still a legit question, but some people react on first impression and move on leaving only the down-vote because they are disgusted by the format a question is represented. My standpoint is instead of down-voting, we should encourage people to do an edit to improve this question. But maybe I'm still seeing good things where others only see bad.
To your second question I cant say much beside that is not really clear to me what is being asked.
To come back to your own question, no that is not malicious up/down-voting continuing, it is just the day to day craziness we see sadly often enough.