I agree. Actually I agree with everything you wrote.
In fact I would go a step further and say that such language is the only language in such a letter that means what it says, because it is uniquely and intentionally devoid of tone. It would be there in essentially the same form no matter what text followed it, no matter what the sender really intended or wanted,. Critically, the recipient knows that and will interpret the request accordingly. They will and should interpret it in the context of what they know or suspect about the sender's goals, motivations, power, credibility, etc. Both will or should also assume that such a letter will become public, and therefore that at least some of the message is aimed at the public, and that different audiences will interpret it differently. Treating the sender or the recipient as automata meaning exactly and only what they say is not a strategy likely to result in a good understanding of the situation.
in order for the Commission to fully analyze vulnerabilities and issues related to voter registration and voting
If this means just what it says, why include it? If the info is public, then I expect it should be accessible without stating a specific purpose. The purpose would also be readily implied by the Commission's name anyway. It is at least plausible, then, that including it is a rhetorical choice ("I'm pursuing a virtuous goal and you should feel motivated to comply") and a political one (it is a Republican talking point that vulnerability to fraud is a bigger issue than suppression).
The Commission is charged with studying the registration and voting processes used in federal
elections and submitting a report to the President of the United States that identifies laws, rules,
policies, activities, strategies, and practices that enhance or undermine the American people’s
confidence in the integrity of federal elections processes.
Again, on its own this seems like a perfectly reasonable sentence - knowing such information is not itself good or bad, but is useful for decision making. In practice, it is an intensely political statement. There's domestic context: with the exception of gross abuses, election integrity is a state not federal responsibility; a conservative Supreme Court decision gutted the Voting Rights Act, reducing federal oversight and permitting a huge number of previously-illegal state level election law changes likely to favor Republicans; now a Republican administration wants all this information. There's the international context: totalitarian governments using voter suppression and intimidation to control election outcomes despite nominally democratic processes; "we kill people based on metadata." There's current events context: this particular administration is already under investigation for possible collusion with a hostile foreign power during the last election; the president openly and publicly asked Russia to hack his opponent.
And how about even this one:
You may submit your responses electronically to ElectionIntegrityStaff@ovp.eop.gov or by
utilizing the Safe Access File Exchange (“SAFE”), which is a secure FTP site the federal
government uses for transferring large data files.
Seems simple, but note that despite the availability of a secure FTP site they're actually also inviting recipients to send large volumes of sensitive data over email. Whether the sender meant it that way or not, it's an obvious possible misunderstanding that suggests the sender isn't trying all that hard to keep the information secure. If they were, they would recognize that recipients are not all experts in keeping data secure and would be much more specific in making sure they submit data securely.