From footnote in the actual report:
Disclosure: I am/we are short ESTA. I wrote this article myself, and it expresses my own opinions. I am not receiving compensation for it (other than from Seeking Alpha). I have no business relationship with any company whose stock is mentioned in this article.
Additional disclosure: The above content was written by Cannell Capital LLC. Cannell Capital LLC has sold but not yet purchased shares of Establishment Labs Holdings, Inc. Cannell Capital LLC may buy or sell shares of Establishment Labs Holdings, Inc.in the future. Cannell Capital LLC does not own shares of any competitor of Establishment Labs Holdings, Inc. This report is provided for informational purposes only. Any implied recommendation as to whether these shares should be sold or bought is explicitly withheld. Caveat emptor.
My Explanation: Basically this means that this investigation has been written by what is known as a short seller. This is where someone makes money if the value of the asset decreases so it is in their interests to make you think the company is bad. I'll also note that when the short report on 17th May 2019 was made the stock traded at $26.09 and it currently trades at $71.97 so if you had invested with them over the last 2 years or so you would have got a 175.8% return on investment. At around 20th March 2020 it hit a low of $11.66 at the same time as the Covid-19 crash so if short sellers cashed out then they doubled their money.
I'll also add that when someone makes a bear case it doesn't mean that the asset is bad but simply that it's overvalued. For example if people were selling a $1 coin for $1.20 then it is logical to be bearish on that trade as eventually the $1 coin will be worth $1 again but there is nothing fundamentally wrong with the coin in question. In the same same way if it was selling at $0.80 then you could be bullish as it's undervalued and will eventually be worth $1 again.
It should be noted that Rosen Legal is well known for filing class action lawsuits (first one to file gets the lawsuit and the legal expenses) but they're not always successful and I can see no evidence that it was. SEC rules dictate that a company when communicating with investors has to be 100% truthful and not hide anything that can materially affect the investment. So once the amendment was filed with SEC I think the matter was probably closed.
If you want another report that praises them and disputes report posted on Lichess blog you can look at
seekingalpha.com/article/4260654-fda-might-inadvertently-implanted-establishment-labs-next-hot-medtech-stock although in that case people writing it gain money if the price goes up so they're also not independent.
Summary: I've not investigated the company in depth so I can't say the company is great but the blog article is biased with author having a financial interest so I wouldn't trust it that much. I can agree that optics of having a breast implant company as a sponsor for women's chess isn't great although I don't know if people would prefer to have no sponsor instead.
Personal Disclosure: I hold no long or short position with ESTA. This is not intended as financial advice so any actions taken as a result of this aren't my responsibility i.e. Caveat emptor
EDIT: I noticed I took the date of second short report by Cannell as date. First short report was published on 10th April and share price dipped from $24.92 on 5th April to $22.01 on 12th April and by 26th April it had recovered to $26.44 so the concerns raised didn't affect the share price that much