No dev team can promise to be CPU only; all they could say is "resistant".
Thats like saying credit cards cant be hacked. Or banks cant be robbed.
People will try to crack a coin, the devs can do nothing but try to make their product resistant to such actions.
Strato
HVC: HRWh3ZpL4ZhGVCM2pS7W98isgoKNLVA4Vw
That these things happen is not okay but some kind of normal today, sadly. And it has i good point too, if a coin can not be hacked its a solid one

Sometimes a bad launch can destroy the good intentions of coindevs.
For the fairness of normal people in mining at the moment, the winner for me is definitly gridcoin, i hope they could build up their system to be very secure in the future!