First, as others have pointed out, it's always been like that up to a point. But that's not the problem with X.

I didn't leave X when Musk acquired Twitter, and I'm not scandalised by people's political positions, even when they're extreme. But a position and behaviour are two very different things (e.g. being a racist vs making a Nazi salute on live television). I left when the atmosphere amplified by the site became... not for me. I won't go into a pub full of football hooligans not because I disagree with their club affiliation but because their conduct creates an atmosphere that's not for me.

As for newspapers (even ignoring those with political party affiliations, something that was common in newspapers' heyday), most of them preserved some kind of civil decorum, and those that didn't weren't read by those who wanted some decorum. How civilised some environment is is not a matter of political position.

Also, there were always some people of influence that held extreme views. But such people behaving in an uncivilised manner in public was less common (and certainly less accepted).