There are a number of old Chinese guys teaching that do not advertise, you need to know someone who knows someone. Is it secret? No. But there is an old Chinese saying that says the nail that stands up, gets pounded down, so not calling attention to themselves may be cultural. It also may be they don't want guys showing up causing problems too.
There was a great Yiquan teacher in NYC I found that was that way...but he passed away shortly after I found out he existed. I believe there is another in Boston and the one I had some minor experience with, who is in NYC, as far as I know, never advertised much either. My Yang Shifu is only found if you know someone in the class or happen to be a member of the community center he teaches at.... but he speaks English, Mandarin, Cantonese and Shanghainese. He also has a class someplace that is all Chinese as well. And all that is paid goes to the centers he is teaching in, he takes none of it.