I don’t even like comparing the stock market to the entire crypto market, because altcoins are part of crypto, and they just drag Bitcoin down when they crash. The real comparison should be stock market vs. Bitcoin - or anything else we want to measure against Bitcoin alone.
the only way altcoins drag bitcoin is when they don’t do well or they end up as scams and now the general perception of cryptocurrency is bad but does it drag bitcoin’s value? not much especially if the altcoin we are talking about is not that famous from the start and didn’t have much followers so it wouldn’t be enough to drag bitcoin’s price down