The Great Firewall of China is a censorship program.

This proposed US legislation puts the power of blocking under the authority of its court system and only in the domain of copyright law. The courts are historically very concerned with upholding 1st Amendment rights to a degree that often (but not always) surpasses analogous rights in many sister liberal democracies. Anything that remotely smells of censorship would come under intense scrutiny.

And in this case, since we are talking about copyright law, the only parties with standing to sue for a block are the IP owners in the first place. So, by definition, this legislation cannot be used for censorship.