Well, yes, it can be dangerous. But many people go when the snow covers everything. You have to be the judge of your own abilities, and know when to turn around.
The main problems are when people try to climb or descend on hard and slippery ice, and they don't have the right gear. If you cover the steeper areas when the temperatures are higher, so the snow is softer, you would be a lot better off.
Here are two accidents from last year. Don't be like them:
Watch the videos of this one: Mt Whitney multiple injuries on 6/10/18
. I think people with less than the best ice gear got too high on the mountain where it was too cold and icy for their equipment.
Nobody noticed this guy took the wrong way down: Fatal: Hiker fell on Whitney 2018-05-05