I'd suggest most of the arrests were for being drunk and abusive. Most of the 'trouble' was guys on a packed terracing opening up in a big gap whilst a handful of punters went at it in the middle. More often than not nobody got hurt and it came to nothing. In fairness, the throwing of bottles and cans was pretty grim and we are well shot of that.
I've gone to games against the Dhims in the dim and distant past where I've travelled with a Celtic-supporting mate, we've parked the car, gone our separate ways and then met up again after the match driven home and gone for a pint.
I wouldn't dream of it these days - and actually go out of my way to avoid talking football with any of 'them' - and agree that the 'hatred', as you put, it is much, much worse.