I agree with both perspectives. As Scott mentioned, the entire debate comes down to how you define art and design. If you define art as being a very broad and inclusive field that covers more than the traditional fine arts, then yes certainly design falls into that spectrum.
I think the biggest problem is when you start equating the two. You might say that “all designers are artists” (but to be honest I don’t know if I’m a very good artists) but you certainly couldn’t say that “all artists are designers”.