I can see how there could be bias in determining what is lawful, but that's not hypocrisy.
In principle, this move shifts decisions from private global corporate power brokers to national representative government. Facebook and Twitter are private, but they've become so powerful and influential that they function like utilities used for communication. It is better to subject these platforms to laws that can be checked by representative government than to the whims of tech oligarchs.
Unsurprisingly the "who" above is the proponents of the bill and, as the OP notes, they don't exactly have a track record of protecting free speech which makes it even more hypocritical.
> “[...]” wrote the prime minister, Mateusz Morawiecki, on Facebook earlier this week, [...]. “There can be no consent to censorship.”
This is consistent only if censorship does not include removing illegal speech, which I don't think is a very widespread definition.