English Translation
He was forced to sign the document.
Shouldn’t this be obligó?
He was forced to sign the document.
Shouldn’t this be obligó?
No. The English sentence is passive, but the Spanish isn’t.
The plural verb is typical when the subject is an indefinite ‘someone’.
Other possibilities are “se le obligó” or “fue obligado”.
Google Ngrams shows the following statistics:
se le obligó 0.0000081997%
le obligaron 0.0000273102%
fue obligado 0.0000507582%