Context: Chat Control 2.0: EU governments set to approve the end of private messaging and secure encryption
"By making a minor concession EU governments hope to find a majority next week to approve the controversial 'chat control' bill. According to the proposed child sexual abuse regulation (CSAR), providers of messengers, e-mail and chat services would be forced to automatically search all private messages and photos for suspicious content and report it to the EU. To find a majority for this unprecedented mass surveillance, the EU Council Presidency proposed Tuesday that the scanners would initially search for previously classified CSAM only, and even less reliable technology to classify unknown imagery or conversations would be reserved to a later stage. The proposed „deal“ will be discussed by ambassadors tomorrow and could be adopted by ministers next week."
This is not a random thing thrown around, though it should be noted that those more involved in this side of "EU bad" usually advocate for remaking the EU, due to the deep systemic issues rather than leaving it. I believe a more mainstream version of this idea is given a stage by Macron (AFAIK he mostly wants to remove the requirement for every country to agree to some things), but moreso from this angle some Pirate Parties (PPP for example) advocate for it.
Quote from PPP's programee (translated by yours truly, though I focused on translating it as directly as possible so it might sound a bit weird):
While this is quite different to "we should leave the EU" it reflects the concerns of those who say that due to policies like this. As far as I know, Brexit was caused more by Brits not liking economic policies of the European Union, though I am not that knowledgeable about UK politics.
TL;DR: you can say EU bad while still wanting an EU I guess.
I'm not that knowledgeable, being an American, but my understanding is that Brexit was mainly the result of racism, and of English people falling for easily disproven lies about the economic impact of EU membership. I'd like to think that what I lack in direct experience of British politics, I make up for with direct experience of the exact same bullshit in American politics.