Now in general I do think Jason is the strongest. He's the tallest in canon and depending on the artist sometimes he's the most bulked up. Anyway one of the theories I've seen which isn't listed in the post I linked is that Jason has increased strength because of his rebirth although it's not as great as Damians' brief power jump. I'm not sure I'm sold on this train of thought yet but it's definitely interesting to look at the examples. Let's look at the examples given in the post:
- Jason holding up part of a building (?!) to allow people to escape. I'm guessing it's from Batman and Robin Eternal? I have no idea what the context is or if it's explained but that looks like A LOT of weight he's holding up. He does say he's not Superman (despite the seemingly inhuman strength shown) and can't keep it up all day.
- Arkham Knight drags Bane. It's different canon but I suppose I can chalk this up to his armor making this possible.
- Jason being able to pull away from Supergirls' grip. While it was never explained in the actual issue the solicits say he's on Venom during this time. That doesn't fit into canon as Jason only used it once (it burned out quickly), then stayed with Roy when he was close to death, looked for Kori right after and dumped all the drugs. He had no logical time to see Supergirl during the Venom period so I like to ignore it all together. Regardless it's still iffy if he could pull away from her while using Venom.
- Pulling a rope by himself? I'm not sure why this is an example. Everyone is pulling Jason just happens to be doing it without another person pulling on the same rope. I don't recall but it might have simply been because there weren't anymore people available to help.
- Jason flips Suzie Su. It's not strength it's using her weight against her. I think that's Judo. In real life you can flip someone who weighs more than you with proper training.
There's also this bit I remembered while looking at the examples.
We Are Robin #7- During Robin War Jason and Tim are forced into a pointless fight. It ends with Jason basically kicking Tim up towards the cells/cages hanging on the ceiling. ...That would take some serious leg muscles.