Me? I'd be very surprised if they can actually read encrypted messages (without pushing a malicious client update). The odds that no one at Meta would blow the whistle seem low, and a backdoor would likely be discovered by independent security researchers.
If there is such a back door, it would hardly follow it's widely known within the company. From the sparse reports on why Facebook/Meta has been caught doing this in the past, it's for favor trading and leverage at the highest levels.
That was my reaction on reading the headline. Of course Meta can read them, they own the entire stack. The question would really be do they?
Is there an independent audit of the Whatsapp client and of the servers?
I'd be surprised as well. I know people who've worked on the WhatsApp apps specifically for years. It feels highly unlikely that they wouldn't have come across this backdoor and they wouldn't have mentioned it to me.
Happy to bet $100 that this lawsuit goes nowhere.