No that's not True. Roku works just fine on my 2008 Samsung non-smart, Roku doesn't know whether a TV is smart or not. The TV needs HDMI and hopefully 1080p.
There have been cases where Roku's autodetect has sent 1080p to 1080i-only sets and that doesn't work. I think that can usually be worked around by setting the Roku to 720p instead of auto.
Banned but back. Because why not?