Firsten's grammaticality judgements may be fine, depending on your dialect, but his explanation is way off. He explains that foregrounding we is odd because it's the potential subject of least importance. This is nonsense plain and simple. The sentence can easily be rephrased as
I find the following passive sentences rather strange:
1. We were explained this theorem by our new math teacher.
2. He was conferred an honorary degree by MIT.
3. He was administered the oath yesterday.
Do you find them well formed or natural?
Narsu K. Nihalani
Aurangabad, Maharashtra, India
Your first sentence is not ungrammatical, but it's a perfect example of forcing the use of the passive voice when it shouldn't be used. Of the three potential subjects that the sentence contains (we, this theorem, our new math teacher), the subject of least importance is we. To my way of thinking, that's why the sentence comes off as so unnatural and almost silly. The whole point of the passive voice in such an instance is for the speaker or writer to show which person or thing is the focus. If it’s the theorem, the sentence should be in the passive voice:
This theorem was explained to us by our new math teacher.
And if it's the math teacher, the sentence should be in the active voice:
The new math teacher explained this theorem to us.
I can argue a case for saying We were explained this theorem by our new math teacher if the speaker or writer needs to focus on himself and his fellow students, but it certainly is an awkward way to express this idea.
As to the other two sentences, because the agent—the doer—is not mentioned, those sentences look and sound perfectly fine.
- We listened to our math teacher's explanation of the theorem.
1A. Our new math teacher explained us this theorem.
2A. MIT conferred him an honorary degree.
3A. They administered him the oath yesterday.
4A. They gave him the medal of honour.
or do you only accept
1B. Our new math teacher explained this theorem to us.
2B. MIT conferred an honorary degree (up)on him.
3B. They administered the oath to him yesterday.
4B. They gave the medal of honour to him.
For some people, all sentences are grammatical, for others only the last five are. Personally, I'm in between. I find 2A and 3A marginally acceptable, but 1A is out of the question for me. If you find any of the A sentences acceptable (4A is beyond reproach), you'll find the corresponding passive acceptable as well. But if you accept only the B sentences, then in the passive, the direct object has to be fronted, not the object of the preposition. Thus, you would get:
1. This theorem was explained to us by our new math teacher.
2. An honorary degree was conferred (up)on him by MIT.
3. The oath was administered to him yesterday.