So many ifs in this thread! It sounds like no-one has ever got really angry with you in reality for using the wrong pronouns, right? I’ve never experienced anything other than a polite correction. The person you’re replying to also doesn’t describe any such experience. They said (1) that someone they met loudly emphasized their preferred pronouns and (2) that they went to an event where some people put neopronouns on their name badges.
I don't know the name's of 75% of the people I work with (I work with a 100+ people a week) and I really have no time or inclination to make the effort. If someone makes up pronouns that don't correspond to their image they are going to get mad at me because I am pretty much incapable of remembering their name let alone their pronouns. If I remember, cool I will use them but I'm really not going to spend hours practicing. Its not an intentional insult, I want everyone to be happy, I just don't have the effort or inclination in me to expend on it.