Because it might like we are talking about similar things, but we are not. A random person checking your ID to, I don't, know, sell you booze won't store that date, won't cross-reference that data with other databases, won't leak your ID, won't surveil what you do with the booze, etc.

"But if you show your ID for [add some specific real-life scenario here] what's the issue of "showing" your ID to access certain webpages?

In 99% of the cases it just doesn't make sense. The logic is COMPLETELY different. Web surfing is not the same as walking on a street.