TL;DR - you are wrong.
Ryu has lost to a lot of characters. Looking at the comic, he lost the rematch with Sagat, he lost to Cody, Ken, Rose, and also a few others. In the game canon though, it isn’t clear exactly who he’s beaten because the canon isn’t clear.
In SF1 it was said that Ryu was beaten by Sagat, and when the fight was over, after Ryu was down, Sagat went over to help him up and Ryu unleashed a surprise attack. After Ryu lost to Sagat, that is when his desire for victory took over and he succumbed to the Satsui No Hado. The Dark Hado made him almost kill Sagat in athatsurprise attack, and after that “victory” is when Ryu’s struggle with the Dark Hado began. In the years after than battle, his struggle cost him a bout with Ken (SFA2) and yeah, Akuma beat him at this point too (SFA2) but Akuma would have won anyway; Sagat decided not to fight him a second time because Ryu seemed afflicted (SFA3); but after that Ryu did defeat Bison after Chun and Charlie destroyed his psycho-drive (SFA3). In SF2 it was said that Ryu defeated just about everyone except Bison (in his new body) and Akuma (again), though there was no mention of the Satsui No Hado, and that is then we get to SF4.
In SF4 we don’t know how things when down, but we do know he was still afflicted with the Dark Hado, and that it is here that he begins to realize he can use the power of nothingness as well (keep in mind that Ryu CANNOT control either the Dark Hado or the power of Nothingness at will). SFV and SF3 IMO shouldn’t even be taken into account due to there stories not being know/resolved respectively, but you are right that Ryu would have lost to Oro, and may have won his rematch with Ken during that time.
So as you can see in the game canon, Ryu is indeed a strong opponent, having ran through much of the competition in SF2, but prior to that, and even after that, he was loosing fights and/or running even with most everyone. Taking the comics into consideration as well, most of which happening during the SFA timeline, Ryu has lost many times throughout his travels in the world.
Looking at Jago though, and lets start in season 1, just look at the fact that his entire purpose was to find an opponent who could defeat him and purge him of his corruption…he never found that opponent. It would seem that Jago defeated all comers just as Ryu did in SF2, probably worse though, and that through combat the corruption, Omen, had become stronger, to the point where he fought for control of Jago’ body…hence Shadow Jago. The only “person” who defeated Shadow Jago was Jago, and as such, Omen proper was born.
Season 2 Jago though, was different…weakened by his battle with Omen…and the fight with Riptor and her pack was clear evidence of that…
Jago was different after he purged Omen, and was struggling with regaining his strength (it would seem). Still though, even Aria knew that Jago was potentially the strongest of the Earth’s fighters…
And Jago’s loss to Aganos also shouldn’t be held against him here in this thread imo. Aganos is canonically one of the strongest characters in KI as he rivals Kan-ra in power straight up. He’s so powerful that Kan-ra had to trick him to gain the upper hand to defeat him. After Cinder took control of Aganos in his weakened state and turned him to their side, Aria pretty much automatically put him at the top of the list saying that he was one of the strongest UItra-tech soldiers…
Bottom line is that Ryu has never faced anything like a pack of Riptors, or a character as resilient as Aganos for that matter. Sure Akuma and Oro are VERY powerful characters, whom he cannot defeat, but yeah, I’d say if you put Ryu in the same circumstance that Jago was in, that Ryu would loose too.
About Jago loosing to Cinder and Fulgore, it would seem that you are talking about Jago “loosing” when Maya’s temple was raided by UT forces. That wasn’t Jago loosing, that was Jago and the other good guys surviving UT’s onslaught. Jago apparently went up against multiple MKII Fulgores, and may have fought Cinder too. At the end of the day though, Jago didn’t die, he survived the massive battle that occurred there.
Finally, you think the Satsui No Hado is more powerful than the power of Gargos? Why?