That was what we thought ten years ago. There has been considerable and surprising progress on ice sheet dynamics. Basically, ice sheets do not melt from the top. They crack, fail mechanically, and slip into the sea. This is especially true of those whose base is below sea level, specifically the West Antarctic Ice sheet (WAIS).
14 Ka ago sea level rose by several meters per century for several centuries. The mechanism was the partial failure of the WAIS. There's still some left.
Don't get me wrong; this will not happen next week, and there will be no resulting tsunami. But a meter of sea level rise in this century is likely, two is plausible, and four isn't totally excluded.
You seem fond of don't-worry arguments. This makes you an instance of Eliezer's point.
The Milankovic forcing is small. Even in the unforced case we would probably miss the next trigger and have 50 Ka of peace and quiet. Now we're well past the threshhold. Find something else to worry about, please, like ocean acidification, coastal flooding, rapid regional climate shifts, and ecosystem disruption for instance.