Because it can overwhelm our healthcare system. A 1% mortality rate means 3.6 million infected will die and with those numbers, the mortality rate will become far higher as hard choices are made on who to save and who to let die simply because we can’t care for them.
You feel feel it is not that deadly? Tell, that to the thousands that will die and the thousands more who may die if we don’t keep it contained.
And if you think your age or condition spares you, you may be dead wrong. Healthy individuals far younger than you are dying and you aren’t anything special.