A court ordering for social media accounts to be blocked is censorship, no question about that.

If there are "election rules" that regulate what can be posted online, that's censorship. Even if people are inciting violence or formenting revolution, banning them is censorship.

Most governments participate in censorship, and most people are OK with some level of censorship. But Brazil's constitution guarantees freedom of speech without censorship, so their courts have no business issuing orders to censor social media.