https://www.fcc.gov/consumers/guides/loud-commercials-tv ROKU violates this rule, especially with wal- mart ads
Pretty sure there is no FEC (Federal Election Commission) violation with the loud ads, but there might be an FCC violation - you might want to correct your subject/title.
Regardless, you have to report the violation to the FCC (not to Roku):
https://consumercomplaints.fcc.gov/hc/en-us/requests/new?ticket_form_id=33794
You might also consider using a volume mode (leveling/night etc) when the ads start, or otherwise use the mute function of your TV.