how do some people have more Blitz elo than rapid

I honestly think it depends very much on the player and their fortes... personally, my blitz is far lower than my rapid - partly because I've only recently started playing it, but mostly because of my chronic ability to panic in time difficulties. Everyone is different - some people excel at blitz but perform worse in slower time controls where they have to calculate more. It should theoretically level out as you reach higher elos, but I'm still waiting on that for me!

Faster time controls have a stronger player pool,
so it is logical for ratings to be lower in the faster time controls.

Some people specialise in fast time controls: flagging, premoving, moving fast... and their rating is higher in the fast time controls, contrary to the trend.

gg

why does levy play blitz,why does gm carlsen,gm hikaru play blitz

Because it's the most competitive time control.

I'm 600 something in blitz and 1300 in rapid. Got a buddy who is damn near 1000 who beats everytime in blitz but I mop the floor with him in rapid. However, I learned chess from an old guy across the street and we never played with a Timer. That's probably why.