If that were true, why then are they not answering with "That is be Theresa May"?In at least some regional variants of English, the word "would" can be used to essentially mean "is" [Q: "What is the name of the Prime Minister?" A: "That would be Theresa May"].
Surely "would be" may be used as "is"; not just "would" on its own - "The name of the Prime Minister would be Theresa May" would be correct
"The name of the Prime Minister would Theresa May" does not make sense.