Strange as it may seem, it’s correct as written. Another example of the bare infinitive as a predicate nominative after “to be”: “The only thing to do is go forward.” If we put the verb in the subject position, then it’s the gerund as usual: Learning a few Italian words and eating is all I have done.” I’m afraid I can’t remember the name of the rule.

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It is the case where the Infinitive is as a part of the Compound Nominal Predicate, the usual form is a bare infinitival ("be"), but "to" can optionally be added