Bitcoin fixes it by reducing the number of scammers in the chain. if you deal with a seller and paypal, either the paypal or the seller can scam you. paypal is immune to bad press because their reputation is already rock bottom, so they don't even lose any reputation anymore by rampantly thieving and scamming. At least if, with a cryptocurrency, the seller scams you, you can voice it somewhere their reputation will be at risk. It doesn't delete the risk but the fixes the problem of "middle man is a scammer and thief and nobody is willing to do anything at all about it" that exists with paypal.
There's nobody you can complain to to get your money back from paypal in many situations, especially when it comes to receiving payments. If you use a credit card or have a bank send them money you have better options, but many people scammed by paypal have no recourse when they are on the receiving end of the money (which is the primary reason you'd have money held in paypal to begin with, as typically if you're sending it along you're not letting it sit there in the account).
