I wonder how many TV brands that include Roku on their TVs will dump them going forward especially for the non-american markets.

Well, I certainly will never buy another one. I doubt I am alone.

Sadly there are enough loyal fanatics that I can imagine they will continue to be sold indefinitely.

Wouldn't somebody who boycotts a company to boycott a different company to boycott a third company be the fanatic in this case?

The companies become one after the purchase. That's how purchases work.