Adding the word "historically" to a question doesn't make the question any more meaningful or on-topic, any more than adding the phrase "as a programmer""as a programmer" makes it more relevant to programmers. Asking what someone thought about something in the past rather than today doesn't make it any less opinion-based.
What matters is whether someone is able to cite their sources. If a person can demonstrate that they had first-hand knowledge of the decision-making process, or can point to an Internet post from an authoritative source that describes the decision making process, that is what makes the post less opinion-based.
A question that merely asks for proof or citations is off-topic, it being primarily a search request.