The very first sentence of the communications act of 1934 says the FCC exists to regulate communication by wire, congress need not pass a law granting it[1]. And what wording could the new law possibly use that is more explicit than the existing "for the purpose of regulating interstate and foreign commerce in communication by wire"

It's inexplicable that the same party that claims the act establishing the FCC is more limited than the wording states while the federal arbitration act is continuously expanded to cover cases that neither the authors nor previous courts ever tolerated.

[1]https://transition.fcc.gov/Reports/1934new.pdf