That's fair, but I don't think (I could be wrong!) that Peyton Manning and his hard drawl got that type of criticism, but it's everywhere with Lamar, by all races. Mixing the accent with AAVE might just push some over the edge. I dunno.
But Peyton didn't articulate himself in a dumb manner though.
Lamar Jackson, at times, just says things that don't sound like something a smart person would say. Peyton never did that.
That's why, for me at least, I think accent plays a role but its more than that.
Now, that being said...he also could be a young kid that gets nervous in front of the media and the camera and just comes across totally different than he actually is. Obviously, we don't see him outside of that and, as Chris said, it may not be fair to criticize him for it. Based on what we have seen and heard, I don't think Ricker is wrong but it also doesn't mean that Ricker is right.