Altcoins are counterfeit. Bitcoin requires proof of work. Everyone plays by the same rules. Printing your own money costs nothing. Premine, sell a portion of it, pay VCs and marketing agencies to promote it.

They're very detrimental to Bitcoin as normies are not sufficiently informed to know the difference and Bitcoin is tainted by association. Anyone enabling this negative feedback loop of fraud and grift is standing in the way of the only chance we'll ever have to fix money.