That's an oversimplifcation.

Bitcoin exists so that there's a decentralized digital currency that, at the base level, does not allow chargebacks, just as physical cash does not.

However, Bitcoin is certainly not intended to prevent people who want such a feature from layering a chargeback-allowing protocol on top of the basic Bitcoin protocol, for users who really want such a feature.  This is the role played by Bitcoin escrow services, and whatever other services people are coming up with.

Similarly, physical cash does not itself allow chargebacks, but it allows people to layer systems on top of this that allow chargebacks.

Bitcoin is supposed to take the role of cash, not prevent analogous mechanisms from interfacing with it to reduce the reliance on trust between the transacting parties.

Still, to the extent that you want to modify the Bitcoin protocol *itself* to allow chargebacks, you can GTFO and take your phail with you.