The scene on the IRS.gov home page of the US tax authority, January 2016 (and still present a year later):
YouTube is a commercial entity, with numerous competitors. Unless you'd be okay with a McDonalds or Coca-Cola product placement on a government site built with your tax dollars, you probably shouldn't be okay with this either...
And it's getting worse:
If you don't want to see government sites plastered with corporate logos,
and don't want to have to go to private-company websites and app stores
to participate in your democracy, please consider contacting your
elected representatives now.
This stuff matters; freedom endures only as long as diligence.