Read the comments here and you'll quickly see why it's a problem. There are multiple reasons.

1. Sony will use this for tracking and advertising.
2. Having a Sony account has proven to be not safe, many times...

• April 2011: Hackers Access Personal Data of 77 Million Sony PlayStation Network Users
• May 2011: Personal Details on 25 Million Sony Online Entertainment Customers Stolen
• June 2011: Sony Pictures Website Hacked, Exposing One Million Accounts
• November 2014: Hackers Steal 100 Terabytes of Data from Sony Pictures
• August 2017: Hacker Group Accesses Sony Social Media Accounts
• September 2023: Sony Investigates Alleged Hack
• October 2023: Sony Notifies Employees of Data Breach

3. They only included that this was needed in some places, and even there in small print. Which we all now is on purpose and is disgusting corporate behaviour.
4. People who have bought the game and can't make a PSN account have now lost access to the game they probably paid full price for.
5. I addition to those, imagine this new trend where each publisher is requires you to make an account withim their systems and having to link them whenever you want to play their game.. That could mean you would now need an account for:

EA, Activision Blizzard, Ubisoft, Take-Two Interactive, Square Enix, Capcom, Bandai Namco, Bethesda, Nintendo, Sony, Microsoft Studios, Warner Bros. Interactive Entertainment, Sega, Konami, THQ Nordic, 2K Games, Paradox Interactive, Focus Home Interactive, Devolver Digital....... Etc....

And that's only a small portion of the number of publishers... It's a trend that benefits the publishers only as they get to track users on a new level. Honestly boils my blood the amount of corporate greed were seeing in the gaming industry.