A lot of Hispanic people apparently listen to KKMO out of Tacoma. It's still on the air, and still has advertisers. If your argument that AM's audience primarily consists of older, conservative white men, how does KKMO stay in business?
And where on FM is any Punjabi broadcasting, especially in Seattle? KKDZ is not available on TuneIn (its page is presently 404 on my computer), and they don't seem to have their own stream.
If you want to hear a certain type of media, you go to where that media is available. Or you find alternatives. Both are factors that all radio stations, of every format, increasingly face.