Tesla wants people to believe in them in order to continue selling cars to customers (who probably wouldn't buy if they thought the company was going bankrupt) and stock/bonds already issued to investors.
Short sellers want to give people doubt to cause a decrease in stock price in order to benefit from their short position.
Both parties are probably acting in good faith - Tesla wants people to see how good they are and short sellers want people to see how risky they are. But as a result the news is crowded and it's generally hard to know the truth.
Just remember, in the US the Supreme Court has ruled that it's legal for news publications to lie to their readers/viewers.