Dealing with unpleasant people in conferences
Unpleasant people? If you are convinced that you did not do anything to deserve their castigation (and from your story, it sounds like you didn't), purse your lips, raise a slight Spock brow, wait a second, and go/look somewhere else. Nothing shows your opinion about them more clearly than this wordless sequence. They will be seething, but you have better things to do.
If you can not avoid interacting with them, be unwaveringly polite, but distant. You may even exaggerate the politeness by using &quot;Sir&quot; etc. This increases distance.
It's not your job to educate someone who failed to learn basic manners at school. Their manners are not your responsibility.
If they stalk you at a conference, indifference is another strategy. Non-reactivity is boring and they will look for a more reactive victim.
Of course, many conferences have these code-of-conduct declarations now and you could try to invoke them, but I have no idea how effective that is in a case like yours.
Personally, I distrust the effectiveness of formalized rules of behaviour for anything but really egregious and obvious breaches of conduct, and even then I am not sure they really work, unless you belong to a well-delineated group that is seen as requiring special protection. But, your mileage may vary.