Literally anybody can spend a buck or so to send 69 doge to that address, and then use it to promote their pump-and-dump.
You can't tell that transfers into an address are done with the consent of the address owner at all, or that they represent "buying". The only activity that is provably initiated by the address owner are the transfers out, and none of those are meme amounts. In fact they're all to a single wallet. Probably the exchange's hot wallet.
yesterday just bought another 100M.
Is not an exchange, because don't sell just buy more a more. Exchange wallets are easy to detect looking to the massive amount of transactions.