Many jurists do accept that it is appropriate to attempt to ascertain the "legislative intent" as part of the exercise of statutory interpretation, but legislative intent is not an aggregate of the subjective intentions of individual legislators. I am not aware of any question of statutory interpretation that was informed by testimony from staffers or legislators who drafted, debated, or enacted a law.
For some rationale, see Judge Easterbrook's foreward to Antonin Scalia and Bryan Garner's Reading Law: The Interpretation of Legal Texts:
Legislative intent is a fiction, a back-formation from other and often undisclosed sources. Every legislator has an intent, which usually cannot be discovered, since most say nothing before voting on most bills; and the legislature is a collective body that does not have a mind; it "intends" only that the text be adopted, and statutory texts usually are compromises that match no one's first preference.
If some legislators say one thing and others say something else... how does the interpreter choose which path to follow?
canada
Even evidence of what was said in Parliamentary debate is treated cautiously (R. v. Heywood, [1994] 3 S.C.R. 761):
First, the intent of particular members of Parliament is not the same as the intent of the Parliament as a whole. Thus, it may be said that the corporate will of the legislature is only found in the text of provisions which are passed into law. Second, the political nature of Parliamentary debates brings into question the reliability of the statements made. Different members of the legislature may have different purposes in putting forward their positions. That is to say the statements of a member made in the heat of debate or in committee hearings may not reflect even that member's position at the time of the final vote on the legislation.
Legislative intent is determined by looking at the words, the scheme, and the object of the provision (R. v. Hutchinson, 2014 SCC 19, paragraph 16).