Yes I know.
Except when they use federally licensed public airwaves.
The United States has a long history of media in languages other than English. It is very unlikely that they would do something to offend groups that voted for the current President in very significant percentages. Without entering into partisan political points, if one looks at Hispanics who actually voted, the attitude toward the current administration is high, so I doubt the government would regulate language on radio and TV; this would be unfavorable among their own voters and certainly violate freedom of expression principles.
In other words, thinking that the FCC might restrict foreign language programming is not a valid point.
I understand all that. The FCC became aware of it because the station was broadcasting in English. Most people don't know what Spanish radio stations are saying because they don't speak the language. It's very possible for the FCC to claim national security in requiring licensed stations to broadcast in English to follow the president's EO.
About one in five legal Americans today is Hispanic/Latino. Most know at least some Spanish and the majority know both English and Spanish.
And, of course, we have Puerto Rico, USA, where the vastly dominant language is Spanish (three radio stations in English out of 120) and at least one state, New Mexico, where English and Spanish are official languages... due in a great part to historical reasons.
We can go to extremes: San Diego would be Saint Jacob, LA would be The Angels, Indio, CA, would be "Indian" and the Rio Grande would be The Big River. "Colorado" would be "Red" and "Nevada" becomes "Snowy". Best of all, "Los Feliz", a neighborhood north of Hollywood Boulevard, would be "The Happies".