It's a combination. If you didn't take the time to know how Google works, don't blame it on the groups or the moderators.
If you went over the Google limit of sharing the exact same content to more than three places, you automatically got a Google ding without any moderator having to do anything. That is considered spamming by definition no matter how valuable you think the content is. Google values engagement.
If you are not engaging with others, they will see your content as spam.
10 plus ones is not a stellar achievement. How many folks commented? How many shared? Was the content relevant to the majority of the community members? Are you normally an engaging member of the community?
Google prods you into better behavior by degrees until it removes you from the system.
I've had my community members blocked. I've tried to help them rectify their posts. When they stubbornly didn't respond, I had to remove them from the community. I checked their profile to find more than a dozen clones of the post they dropped in my community littering their posts page.
Google Plus is not a utility company. Neither are any of the other social networks. They are private companies with a private interest. They provide an infrastructure that let's us play, but at the price that makes sense to their business model. FaceBook asks for $$$ for visibility. Google Plus asks for engagement and audience relevance. They ARE a search company.