Human civilization didn’t, because human civilization didn’t exist at the last glacial maximum, and almost all of that rise was before human civilization existed. Low density nomadic hunter-gatherer existence is less disrupted by sea level change than settled agriculture and industry.
What we get is every single existing ocean port city (which is a lot of the largest cities) being threatened by more frequent flooding. They're all right at sea level, because that's where you build port cities. Not all of these cities really depend on being ports any more, but that's how they became major population and business centers.
They don't just pick up and move something like that. There's no place you can say, "Oh, they're going to move New York over to X, so I'll buy land there now". Even if they did for some reason decide that it was so bad they had to abandon New York (or Charleston or San Francisco or lots of others), there's no one place that it goes. The whole human geography of it changes.
[1]https://ocean.si.edu/through-time/ancient-seas/sea-level-ris...
"Whether it takes another 200 or 2000 years largely depends on how quickly the ice sheets melt. Even if global warming were to stop today, sea level would continue to rise."
-- from the same article (2 sentences later)
7 meter rise over 2 centuries can likely be managed in a reasonable manner via land taxation, resettlement, wall, and levy construction. 7 meter rise in 5 years would likely collapse most of the western world as major population centers find themselves unlivably under water.
