I'm of the opinion that opinions about Desmond Ridder were set in stone over the winter when the "smart media" knew Atlanta needed to get Lamar Jackson, because Ridder was a "3rd rounder".

Look, Ridder is "mid." He's 14th in QBR and passer rating. He's not an MVP candidate. He's not a Pro Bowler. He's mid, which is fine in this offense. Anyhoo, I broke down Sunday's game by his plays.
+2 for elite plays
+1 for positive plays
0 for neutral plays
-1 for negative plays
-2 for cut that crap oiut

Drive One
Quick Screen +1
INT as he was hit -1

Drive Two
Short pass that was dropped 0
Threads needle to Smith +2
Overthrows Pitt -1
Pass to Smith +1
Scramble for 1st down +2
Nice pass to Pitts in stride +1
Pass to Robinson +1
9yd run +2
Overthrown pass to Pitts w/ PI 0
Smart throw away 0
Bad throw -1

Drive Three
Batted at LOS -1
4 yd run +1
London 22yd conversion +2
Stuffed short pass 0
Run +1
Should've been INT -2

Drive Four
Quick out +1
Slant +1
Short pass +1
QB Sneak failed 0
Pass to Smith +1
TD to London +2

Drive Five
INC but dropped 0
Incomplete -1
Drop 0
Near INT -2

Drive Six
Screen +1
Covered, thrown away 0
Hollins non-TD (good throw) +1
Sack (no time) 0

Drive Seven
Overthrow, but PI 0
Trick Play to Hollins, underthrown a bit +1
London Short +1
TD Run +2

Drive Eight
1st down scramble +1
Short to Robinson +1
Scramble for gain +1
Off target slant -1

Drive Nine
Pass to London +2
Smart Throw away 0
Short pass +1
Short pass +1
Run +1

For me, that's a plus 24 day. I think the non-interceptions were worse than the actual interception, given the difference between being drilled as you hit the ball and throwing to the wrong jersey. There were few missed targets and a few passes where he might have been able to spring his receivers a bit better, but the point of this offense is to stay "on schedule" with more 4 yard plays than 24 yard plays (though there's a place for the latter).

PFF has Ridder as one of the five worst QBs in the league.

I don't see it. He's decidedly average, but this offense was built for an average QB (with an average QB's salary).