We're writing the men...the "to" is redundant in English, and therefore optional. I had an argument with an English teacher who claimed that one could never have an indirect object without a direct object. I won the argument with this sentence. (It's cheating...I know. The direct object is understood...we wrote a letter or a note.)
It's acceptable English. The indirective object in English is observed from word order, and the "to" is often understood. In a sentence like, "He wrote his parents last night," I teach my students to ask questions: "Who wrote"? He did...He is the subject. "Wrote what?" ...a letter or some form of communication. That's the direct object, in this case, unspoken but understood. "Wrote to whom?" ...to his parents. That's the indirect object, with "to" understood. In German, the noun gets an ending to indicate its use...English jettisoned all endings but the genitive, now called "possessive"...'s or s'.