@Alberto0
Your concern is justified. Airbnb does not carry out the verification process, but since 2013, has outsourced it instead to a controversial start-up called Jumio, which filed for bankruptcy in 2016, following the ousting of founder and CEO Daniel Mattes, amid allegations of financial irregularities.
In response to vehement opposition from other shareholders, a $22.7 million bid by early investor and major shareholder Eduardo Saverin (Facebook co-founder) to buy out the company was blocked by the courts (citing "every red flag possible"), and was sold instead to private equity firm Centana Growth Partners, for just $850,000. (Saverin had resigned from the board just days before Jumio filed for bankruptcy, but remains heavily involved in the rebuilding of Jumio Corp., as its now known)
Saverin and other company executives were later sued by another shareholder, Bloso Investments, who accused them of having "grossly mismanaged" the firm and driving it into bankruptcy, and said they'd been running Jumio without proper financial and accounting controls for years.
The following is a review by an Australian company that signed up for Jumio's identity verification services, but found them sorely lacking
https://www.reddit.com/r/ReviewTechUSA/comments/4go0ph/jumio_review_flawed_product_and_unethical_com...
As regards the reason why verification was required in your case - whether or not its requested by your host, the Airbnb system also randomly selects a certain percentage of users to undergo the verification process. (I'm not quite sure but I think it may be 25%)
Hope you manage to get everything sorted soon.