Right now they are just buying, no one is selling ... interesting.
It is not, that's called shorting and its very common.
In fact alot of strategies that are market neutral work by shorting one stock while being long the other, or similarly a basket of stocks.
I just recall Navinder Singh Sarao "$1T Flash Crash" as a notable addition to a long list of algorithmic trading strategies going sideways ( https://marketrealist.com/who-is-navinder-singh-sarao-the-ma... .)
The stock market was built on information asymmetry, unfair positions, and ambitious gamblers... statistically it is rarely a reasonable investment for amateurs.
Good luck, =3