The letter is signed by J. Randy Forbes of Virginia and Suzan DelBene of Washington
Yes. They're also co-chairs of the Trademark Caucus, a new body (formed just last year) to winkle more dollars out of corporate contributors by promising to rattle sabres in defense of this most trivial form of IP. So this is their job.
And they're the only two signatures, so it's hardly a letter "from the US Congress". Two Reps doth not a Congress make. Had the article said "a letter from nearly 0.4% of the US Congress", it would have been accurate.