I’m sure this is a well loved old title but foxing can happen to newer books too depending on the way they are kept. I have seen cheap paperbacks, stored in a warm humid place, show signs of foxing after a year or two.
Or, people saying to not use their real names aren't doing bad things just because others assume it is true - many maybe grew up in an age where "don't share personal info" was the rule, have seen what happens with swatting or foxing, etc.
And if they choose to get hostile then that’s that. As long as nobody is being harmed then oh well. Call it stupid dumb etc it doesn’t matter. Learn to stop bothering ppl and read the room.. have a conversation first before you go foxing