From their perspective it's ok, but from payer perspective you may not want to be connected with all other payers onchain (risking IP triangulation, etc)

nout

bitcoin

Knowledge crowdsource

purpurato

Whats wrong with this org reusing addresses? Maybe they like the transparency showing their donation amounts by payment method. Its probably easier for people to donate to as well. 

They could use BIP47 payment codes like https://paynym.is/

You make one onchain TX that establishes your payment code onchain, then compatible wallets can request an new address from the payment code. The "server" is the blockchain, plus wallet-side algorithms to generate addresses.