Following what Drew (Mister know-it-all but knows nothing) says about tainting coins does not make the blockchain centralized, I would like you to read this part of a research paper from the University of Zurich, about the decentralization of the bitcoin. This applies to Pac also and any coins.
"Coin Tainting
Given that Bitcoin transactions basically consist of a chain of digital signatures, the expenditure of individual coins can be publicly tracked. This enables any entity to taint coins that belong to aspecific (set of) addresses and monitor their expenditure across the network. The literature features a number of proposals that cluster Bitcoin addresses, and gather behavioural information about these addresses.
Coin tainting is currently used to achieve a degree of accountability in the Bitcoin network; if an address misbehaves, then Bitcoin users can decide to stop interacting with the address (i.e.,not accepting its coins), thus deflating the value of all the coins pertaining to that address. For instance, following a theft of 43,000 BTCs from the Bitcoin trading platform Bitcoinica, the Bitcoin service MtGox traced the stolen BTC and locked accounts that were receiving the tainted coins.These incidents show that powerful entities in Bitcoin canrightfully or notdeflate the value of BTCs owned by specific addresses. If these entities were to cooperate with the handful of developers that have privileged rights in the system, then all Bitcoin users can be warned not to accept BTCs that pertain from a given address (e.g., using alert messages).
Even worse, developers can hard-code a list of banned Bitcoin addresses within the official Bitcoin client releases, thus blocking all interactions with a given Bitcoin address without the consent of users. Furthermore, while coin tainting can be used to punish provably misbehaving addresses, it could also be abused to control the financial flows in the network subject to government pressure,but also due to social activism. This empowers few powerful entities that are not necessarily part of the Bitcoin network, such as governments and activists, to regulate the Bitcoin economy. Even if all Bitcoin decisions and operations were completely decentralizedwhich they are notcoin tainting presents an obstacle to a truly decentralized Bitcoin.
Coin tainting can be especially detrimental if coins are not widely exchanged among Bitcoin addresses. This enables entities to damage only a specific set of addresses, without alienating other addresses in the system. Other users are then also likely to boycott the tainted coins."
I recommend you to read this research paper from here:
https://eprint.iacr.org/2013/829.pdfWell, it is not a paper "from" University of Zürich - only one of the authors appears to be from ETH Zürich actually, and not from University of Zürich.
To the point though: yes, the ability to ban addresses is an inherent property of any blockchain cryptocurrency out there. In my opinion: not banning addresses involved in theft (or any other serious crime) is not really an option, since cryptocurrency should not be financial safe haven for crime, regardless what effects it has on (de)centralisation. The true issue lies when developers of a closed source cryptocurrency project would hide the fact that addresses got banned since this is, mildly put, prone to manipulation with no transparency (even if in some cases the intention might be good). Beyond that, there is always a question on what authority has an address been declared a "criminal" one and got banned from the network - ideally one would have a court order for that, but which court has the expertise and jurisdiction over a world-wide used blockchain with coin owners spread over many continents and countries, particularly if the owner(s) of the addresses are unknown...?