It seems gigantically hypocritical. Because it is.
However, it's worth noting that there's a philosopher who offered a defense of this approach, namely Herbert Marcuse, in his influential 1965 essay, Repressive Tolerance.
He's against the old-fashioned ideal of tolerance. He says it's repressive. But he's in favor of a more advanced kind of tolerance, that is liberating:
You may choose
to block opposite views.
But this is liberation