Is the price of BTC going down because of altscams? In fact, a successful sidescam might push BTC's value up since it would essentially increase the scarcity of the remaining coins.
Scams depress price. Alt scams, exchange scams, pirate@40 scams, these all depress price, reduce confidence, encourage regulation, and suck wealth and productive resources out of the crypto economy. SC scams should be expected to do likewise.