Anyway, there's more than just "bulls vs bears" going on here.
In any case, Elon Musk's 20,000 Model 3 manufactured per month target for late 2017 is incredibly late (See: https://twitter.com/elonmusk/status/881757617416056832). A lot of Tesla bulls don't seem to care however and continue to throw money at the company.
Tesla isn't even at 2000 cars a month, and we're well into 2018. A lot of people are interested in "why" this is happening. Yes, short-sellers are interested, but I'm sure normal investors are wondering why Musk isn't even hitting 10% of his target months later.
The article suggests that the QA group is finding flaws in the manufacturing process. So... yeah. That makes sense for why the Model 3 is late with very, very low production numbers. There's been a lot of speculation in different groups for the failure, but ultimately, the core is that Tesla is not making enough Model 3.