Huh. I may be younger than you are. By the time I got online in the early to mid-nineties the very strong zeitgeist was never to use your real name, nor to post identifying details into (the resultingly anonymized) fora. This was the "on the internet no one knows you're a dog" era, which cartoon (I just looked it up) was from 1993 - way earlier than I'd have guessed!
Social media - starting with the very early ones: Six Degrees, Friendster, maybe MySpace? - weakened that expectation, but (someone tell me if this is accurate) my recollection is that Facebook was the first platform to require realname accounts. I agree with you about the current danger, and though I've never posted anything anywhere that I wouldn't stand behind - trolling just isn't my style - I have, reflecting the pov of my "internet generation", always felt super weird publicly posting anything under my real name.
Nowadays, using your real name is dangerous, lest you get swatted or an angry mob decides to get you fired because you made an off-color joke. Doxxing someone is viewed as a potentially violent act. It's hard to imagine anyone using their real name on Discord for instance, whereas in the days of IRC it was common.