I notice that Chimp supporters always leave these type of statements very open ended. When you make a broad statement like this you might want to clarify exactly how they're stronger. For one, that to me means that you're claiming they're stronger in terms of functional strength and in this case in a situation like a fight.
I would need scientific evidence of that. For one, you realise that chimps are adapted to a different environment? They have shorter, weaker legs which are shorter and weaker than their arms. That alone is going to put them at a massive disadvantage against a strongman lifter who's strnegth base is at his legs and core. They also have less control over their muscles like humans, that is why they flop around in a goofy uncoordinated way when they fight eachother.
The only thing they have over humans as far as I can see is their canines and bite force which have been studied. They're also better at bodyweight type of exercises that involve arm strength because they evolved to swing from tree branches. What do you really have in terms of evidence that they're so superior to our strongest humans?
There is no such think as "chimp supporters". If anything, like the reference I made to bestiality, I advise against any altercation with a wild animal without a weapon in hand. It's not that I want to see chimps fight. It's more that I advise you to carry a rifle if you're gonna be around them.
I've been mauled by a pitbull. I much rather fight an MMA guy than go through that again.
Ok, your points. About the video: yes, it looks like an animal that is considerably stronger than a man. Also, it would take a team of specialists to know if the chimp was being playful, aggressive, and so on. There would never be a consensus on the chimps intentions, as that is a huge question for anyone studying behaviour. The video is meaningless, but shows a dangerous animal, like all wild animals. Do not forget: we are prey, we make tools, use the tools.
The thing is: what is scientifically available answered questions that puzzled scientists, not fighting enthusiasts. For example, researchers wanted to understand if apes could build tools, communicate and so on. So, we know that most apes have the vocal cords very low in the throat.
What is scientifically well-documented, you can search at your own leisure, is that the innervation of non-human apes muscles is different from us. We have a lot more nerve terminals to make better use of coordinated fine motions, whereas other apes have coarser innervation, which makes it impossible for them to perform fine movement. The have muscles adapted to climbing at great speeds, extreme grip and so on.
But chimps do not violate a rule of muscle strength: the muscle cross section determines the force. It happens that at lower body masses, apes have larger muscle cross sections for most relevant muscles, which is how people have poorly estimated these "2X, 5X, 1000X" stronger, that I agree with you, are all wrong. But they have thicker more powerful muscles than us that have large innervation areas: and this is their natural state, without supplemental nutrition, training and so on.
The idea of a fight between a human and an animal is a misunderstanding. We have developed martial arts as a way to defend and attack other humans. Animals have completely different behaviours and intentions. For example, animals do "fight" for mating privileges, but they would never apply that ritual against a human. They can attack to kill and eat. There is no amount of martial arts and strength that can defend a human against a top predator (big cats and so on) triggered to kill. From the ape world, if they attacked a human, it would be defensive or territorial: these kinds of attacks can stop at any moment and so on. But there is no human who could defend himself against a Gorilla. A chimp is debatable: they can be shy, and quickly get scared of a larger creature, so I agree with you that a large human can overpower a chimp. On the other hand, I do not advise any human to try this because the chimp can cause unspeakable harm to the human.
I hope I made myself clear.
