Satoshi has somewhere around one million coins. If these coins were to be sold on the market, it could crash the price.
no one said that those coins will be sold all at once, selling them slowly will not cause any harm
let's say 1k coins per day in 3 years of a time frame, it will be like a major pressure coming from miners
and if he is really satoshi he will not harm bitcoin by selling them and destroying the market