。
He is the one who must be blamed.
Literal
Blamed must [nominalizer-の] [topic-は] he [copula-だ].
Uses ~なくてはいけない ('must') instead of ~べき ('should'), making the obligation stronger. The passive 非難されなくてはいけない places the person as the recipient of the blame obligation — 'must be blamed' rather than 'should be blamed.'