Many conferences these days (at least in my field) have a code of conduct which all attendees agree to abide by when they register. An example from a recent conference is here: https://www.cosmologyfromhome.com/code-of-conduct/
If an attendee breaches the code of conduct (and shouting in that manner at another attendee would certainly constitute such a breach) they can be reported to the conference organisers. The most severe consequence would be asking them to leave the conference.
So, if you are now in a position where you are organising conferences, including a code of conduct would be an excellent thing to do (or suggesting it to the organisers if you are not on the committee).
While the tactic of ignoring the person is another possibility, I worry that this is something of an easy way out. By doing nothing, we are giving tacit approval to harrassers and bullies, effectively emboldening them since they face no consequences for their actions.
We get many questions on this site about how to deal with abusive PhD supervisors and the advice then is never to silently put up with it. Imagine being the PhD student of the person who called you a liar and didn't want to sit next to you at the conference. You were only subjected to that treatment for a day; they could have been subjected to it on a daily basis for years. Think how demoralising it must have felt to have everyone around them ignore this person's behaviour.
I do not, therefore, advocate for ignoring harrassment if you are in a secure enough position to challenge it. Obviously if the harrasser has or could have some power over you in the future, it is sensible not to confront them. But if you are a peer or the senior party, you can at least have a quiet word with that person, or ask them not to talk to people in that way. They probably won't change overnight (or perhaps ever), but it's important not to give the message to junior people that you don't care about harrassing and bullying behaviour.
Another practical thing you can do, if you are now senior in your field, is to warn junior people about the behaviour of such a person, especially if their harrassment is particularly targeted towards junior people. Dissuade them from approaching the person in question. Dissuade them from doing a PhD with or collaborating with them, if you can.