While your numbers, if factual (no source posted), are statistically correct (in that it won't make our species go extinct), you have to remember a simple fact: those numbers represent individual human lives. Family, friends, neighbors, your pizza guy, etc. Pretty brutal to be so flippant about.
Also, this doesn't take into account the potential for cascading environmental system failures that could be caused by such warming. These unknowns could greatly change the equation.
I realize you are mainly arguing the point in response to "existential threats" being bandied about, but it's a weird stance to take here.
Ah, so even the "landed gentry" made the migration... /s