You don't seem to have any knowledge at all about how personal data transfers work in the case of a merger or acquisition. Which is a radically different scenario from two standing independent companies exchanging personal data.
It's common practice and common sense that you get access to customer data when you take over a company, how else would you even run it? This has been true and normal for centuries. The concept still stands when applying the strictest of modern privacy laws, it's called "legitimate business interest". Meaning: there is no business without this data, the personal data is required to deliver the service at all.
So no, it's not a selling of your data, it's a change of control. And no, it does not require your consent.
If you don't want to see accusations of "sensationalist" you shouldn't confidently spread hot takes on topics you don't even seem to comprehend the basics of. And if you then go wrong and get corrective feedback as is happening on the Twitter spread, perhaps not double down.