They refer to Sony's ToS:

If SIE Inc determines that you have violated this Agreement's terms, SIE Inc may itself or may procure the taking of any action to protect its interests such as disabling access to or use of some or all System Software, disabling use of this PS5 system online or offline, termination of your access to PlayStation Network, denial of any warranty, repair or other services provided for your PS5 system, implementation of automatic or mandatory updates or devices intended to discontinue unauthorized use, or reliance on any other remedial efforts as reasonably necessary to prevent the use of modified or unpermitted use of System Software.

Although I've never heard of any reports of that, and I'd love to see it tested in a courtroom. Deliberately bricking someone else's hardware because YOU believe for some reason that they're not using it properly is on a whole other level than just disabling online accounts. It's vindictive.