This has been proposed for every large hack in the history of Bitcoin. Not sure if it was by core devs every time, but the proposal always comes out.

It has never happened. This time will not be different.

Interesting history: Luke-jr (core dev) blacklisted some addresses in a package install of bitcoin he maintained, but this sort of censorship was never in the mainline source.

Source: joined Bitcoin community in early 2011, been enjoying bottomless popcorn ever since :-)