I think Omicron is almost universally mild for those who have had the existing vaccines. And as most people have (here in the UK anyway), I can understand why people are seeing it as mild.
There is an ocean of difference between "it's mild because I am vaccinated" and "it's mild", and the bridge across it is being built on the mental and physical well being of our health care providers around the world.
I'd add that it's extremely disingenuous to hide the fact that high vaccination rates are the sole reason why the same disease spreading like wildfire is not leaving a trail of dead bodies stacked high on it's wake.