To be totally clear, the UK has been a fucked up place for centuries, I don't think Meta fundamentally changed the culture.

Having said that, Facebook, WhatsApp, Instagram, etc are tools that enable political influence over the population at levels that were previously unimaginable. Look into Cambridge Analytica a bit or borrow Mindf*ck: Cambridge Analytica and the Plot to Break America by Christopher Wylie from your local library for details.

Starting as early as 2012 we have evidence that Facebook was pivotal in stoking racial tensions in Myanmar, leading to a genocide.

There's evidence that Meta was a major factor in Brexit, which more specifically relates to my claim with respect to influence in the UK.

The US election in 2016 was clearly influenced by Meta platforms, including taking Russian money to stoke racial tensions in line with the Russian Manifesto, The Foundations of Geopolitics.

I'm currently reading through Careless People by Sarah Wynn-Williams, which is a memoir about how these systems were conceptualized and built at Facebook, and so far I'd recommend it.

Obviously Meta isn't the only problem, Tiktok is clearly a problem of similar size and scope, and other social apps have their own challenges (X being owned by the richest man alive and actively influencing the algorithm, for example), but in many ways Meta is the OG, and blazed the trail for others.