I'm pretty sure it's C. I've ruled out B.Sounds like they're either:
a) a dodgy bunch of cowboys or
b) grown at a rate that their experience and resourcing levels can't keep up or
c) a little bit of both.
The latest issue was classic Tapatalk:
They made an announcement on June 16: Tapatalk Blog – Latest News and Feature Spotlight – Tapatalk SEO and Monetization Update
The announcement said that it is going to be opt-in for paying site owners and opt-out for non-paying site owners. That in itself is shady. After their long history of missteps, it should have been opt-in for everyone.
What's worse is that they made it opt-out for everyone, including paying site owners. Oops, error in their favor.
On top of that, the announcement says Google won't consider it duplicate content (they have no way to ensure that), that Google will always rank the site result above the Tapatalk result (oops, they were wrong about that too), and that they are only copying snippets of posts (oops, they often copied whole posts and entire threads, another error in their favor).