I don't have time to watch that video but:
Margins aren't expected to drop due to R5 and R3 sales, it's due to AMD expecting console ramp ups in the second quarter which are very low margin. R5 and R3 are lower margin than R7 for sure, but still should be higher than console margins and not the reason for dropping their margins from this past quarter. AMD also said that they will be selling prior generation (not Ryzen) chips moving forward as there is still a lot of inventory that they need to get through, though they specifically mentioned motherboards so it sounds like AMD is trying to keep partners happy. Not sure on the low profit margin on Polaris, I didn't see that in the transcript but maybe I just missed it.
I know people are upset about the huge negative reaction to AMD matching expectations in Q1, but it wasn't that which was the main cause of the sell-offs, it was their projection for Q2 as well as not wanting to go into some specifics as to what to expect from Naples launching. Investors really expected margins to see a significant bump with Ryzen fully in the market as well as Vega coming into play. They didn't expect lower guidance for margins or an ambiguous timeline for Naples revenue. Does that mean the crazy drop was deserved? Probably not, but it happens, especially with how much movement has been going on with AMD's stock in a pretty short time frame. If you're long on AMD, this shouldn't change much and if Naples can get some big time customers, cash could start rolling AMD's way with high margins, time will tell but they have positioned themselves to be a healthy company again should they execute their plan smoothly for the rest of the year.